Display device and method of fabricating the same

ABSTRACT

A display device includes a substrate, a first electrode and a second electrode which are spaced apart from each other on the substrate, a first insulating pattern on the substrate to cover at least a portion of each of the first electrode and the second electrode, a light emitting element between the first electrode and the second electrode on the first insulating pattern, a first contact electrode in contact with the first electrode and one end portion of the light emitting element, a second contact electrode in contact with the second electrode and another end portion of the light emitting element, and a second insulating pattern on the light emitting element and of which at least a portion is in contact with each of the first contact electrode and the second contact electrode, wherein the second insulating pattern includes a first upper surface not in contact with the first contact electrode or the second contact electrode.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 16/910,962, filed Jun. 24, 2020, which claims priority to andthe benefit of Korean Patent Application No. 10-2019-0105691 filed onAug. 28, 2019 in the Korean Intellectual Property Office, the entirecontent of each of which is incorporated herein by reference.

BACKGROUND 1. Field

One or more aspects of embodiments of the present disclosure relate to adisplay device and a method of fabricating the same. For example, thepresent disclosure relates to a display device including a plurality ofinsulating patterns and a method of fabricating the same.

2. Description of the Related Art

With the development of multimedia, display devices are becoming moreimportant. In response to this development, various types of displaydevices, such as organic light emitting diode (OLED) display devices,liquid crystal display (LCD) devices, and/or the like, are being used.

An example device for displaying an image of a display device includes adisplay panel such as an OLED panel or an LCD panel. Among the abovepanels, a light emitting display panel may include a light emittingelement. For example, a light emitting diode (LED) may include an OLEDusing (including) an organic material as a fluorescent material, and/oran inorganic LED using (including) an inorganic material as afluorescent material.

SUMMARY

One or more embodiments of the present disclosure provide a displaydevice including a plurality of insulating patterns.

One or more embodiments of the present disclosure also provide a methodof fabricating a display device so as to form a plurality of contactelectrodes using a lift off process in the same process.

It should be noted that objects and embodiments of the presentdisclosure are not limited to the above-described objects andembodiments, and other objects and embodiments of the present disclosureshould be apparent to those skilled in the art from the followingdescriptions.

According to an example embodiment of the present disclosure, a displaydevice includes a substrate, a first electrode and a second electrodespaced apart from each other on the substrate along a first direction, afirst insulating pattern on the substrate to cover at least a portion ofeach of the first electrode and the second electrode, a light emittingelement between the first electrode and the second electrode on thefirst insulating pattern, a first contact electrode in contact with thefirst electrode and one end portion of the light emitting element, asecond contact electrode in contact with the second electrode andanother end portion of the light emitting element, and a secondinsulating pattern on the light emitting element, at least a portion ofthe second insulating pattern being in contact with the first contactelectrode and the second contact electrode, wherein the secondinsulating pattern includes a first upper surface not in contact withthe first contact electrode or the second contact electrode.

In an embodiment, the light emitting element may extend in onedirection, and a width in the first direction of the second insulatingpattern may be smaller than a length in the first direction of the lightemitting element.

In an embodiment, the width of the second insulating pattern may besmaller than a width in the first direction of the first insulatingpattern.

In an embodiment, the second insulating pattern may further include afirst lower surface in contact with the light emitting element and asecond lower surface in contact with the first insulating pattern.

In an embodiment, the display device may further comprise a thirdinsulating pattern between the light emitting element and the firstinsulating pattern, wherein the light emitting element may be in contactwith the first insulating pattern and the third insulating pattern.

In an embodiment, a width in the first direction of the third insulatingpattern may be smaller than that of the second insulating pattern.

In an embodiment, at least a portion of the second lower surface of thesecond insulating pattern may be in contact with the third insulatingpattern.

In an embodiment, the second insulating pattern may include a firstcontact surface in contact with the first contact electrode and a secondcontact surface in contact with the second contact electrode, and thefirst contact surface may be on a first side surface of the secondinsulating pattern, and the second contact surface may be on a secondside surface of the second insulating pattern.

In an embodiment, the first contact surface and the second contactsurface may be not parallel to the first upper surface.

In an embodiment, the first contact surface and the second contactsurface may be perpendicular to the substrate.

In an embodiment, the first contact electrode may further include asecond upper surface connected to the first contact surface, the secondcontact electrode may further include a third upper surface connected tothe second contact surface; and at least one selected from the secondupper surface and the third upper surface may be coplanar with the firstupper surface.

In an embodiment, at least one selected from the second upper surfaceand the third upper surface may be spaced apart from a reference surfacedefined by the first upper surface.

In an embodiment, the first contact electrode may be in contact with aside surface of the one end portion of the light emitting element, andthe second contact electrode may be in contact with a side surface ofthe other end portion of the light emitting element.

According to another embodiment of the present disclosure, a displaydevice comprises a first electrode extending in a first direction, asecond electrode extending in the first direction and spaced apart fromthe first electrode in a second direction crossing the first direction,a light emitting element between the first electrode and the secondelectrode, a first contact electrode on the first electrode and incontact with one end portion of the light emitting element, a secondcontact electrode on the second electrode and in contact with the otherend portion of the light emitting element, and an insulating pattern onthe light emitting element between the first contact electrode and thesecond contact electrode, the insulating pattern including a first sidesurface and a second side surface facing the first side surface, whereinthe insulating pattern extends in the first direction, the first sidesurface is in contact with the first contact electrode, and the secondside surface is in contact with the second contact electrode.

In an embodiment, a width in the second direction of the insulatingpattern may be equal to a width in the second direction of a regionbetween the first contact electrode and the second contact electrode.

In an embodiment, the light emitting element may extend in the seconddirection, and the width of the insulating pattern may be smaller than alength in the second direction of the light emitting element.

According to another embodiment of the present disclosure, a method offabricating a display device comprises forming a first electrode and asecond electrode on a substrate, forming a light emitting elementbetween the first electrode and the second electrode, forming aninsulating layer on the light emitting element, forming a lift off layeron the insulating layer and patterning the insulating layer to form aninsulating pattern on the light emitting element, forming a metal layeron the first electrode, the second electrode, and the lift off layer,removing the lift off layer, and forming a first contact electrode incontact with one side surface of the insulating pattern and a secondcontact electrode in contact with another side surface of the insulatingpattern.

In an embodiment, the first contact electrode may be in contact with thefirst electrode and one end portion of the light emitting element, andthe second contact electrode may be in contact with the second electrodeand another end portion of the light emitting element.

In an embodiment, an upper surface of the insulating pattern may be notin contact with the first contact electrode or the second contactelectrode.

In an embodiment, the forming of the lift off layer may further includeforming a hard mask layer between the insulating layer and the lift offlayer, and the insulating pattern may include a region in which the oneside surface and the other side surface are exposed and are not incontact with the first contact electrode or the second contactelectrode.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and features of the present disclosure willbecome more apparent by describing exemplary embodiments thereof in moredetail with reference to the attached drawings, in which:

FIG. 1 is a schematic plan view of a display device according to oneembodiment;

FIG. 2 is a schematic plan view of one pixel of the display deviceaccording to one embodiment;

FIG. 3 is a plan view illustrating one sub-pixel of FIG. 2 ;

FIG. 4 shows cross-sectional views taken along lines Xa-Xa′, Xb-Xb′, andXc-Xc′ of FIG. 3 ;

FIG. 5 is a cross-sectional view illustrating a portion of thecross-sectional view of FIG. 4 taken along line Xb-Xb′;

FIG. 6 is a cross-sectional view taken along line Xd-Xd′ of FIG. 3 ;

FIG. 7 is a schematic view of a light emitting element according to oneembodiment;

FIG. 8 is a flowchart illustrating a method of fabricating a displaydevice according to one embodiment;

FIGS. 9-18 are cross-sectional views illustrating a process offabricating a display device according to one embodiment;

FIG. 19 is a cross-sectional view illustrating a portion of a displaydevice according to another embodiment;

FIGS. 20-23 are cross-sectional views illustrating a process offabricating the display device of FIG. 19 ;

FIG. 24 is a cross-sectional view illustrating a portion of a displaydevice according to still another embodiment;

FIG. 25 is a cross-sectional view illustrating a portion of a displaydevice according to yet another embodiment;

FIG. 26 is a plan view of one sub-pixel of the display device accordingto another embodiment;

FIG. 27 is a schematic view of a light emitting element according toanother embodiment; and

FIG. 28 is a cross-sectional view illustrating a portion of a displaydevice including the light emitting element of FIG. 27 .

DETAILED DESCRIPTION

The subject matter of the present disclosure will now be described morefully hereinafter with reference to the accompanying drawings, in whichexample embodiments of the present disclosure are shown. The subjectmatter of the present disclosure may, however, be embodied in differentforms and should not be construed as limited to the embodiments setforth herein. Rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will filly convey thescope of the present disclosure to those skilled in the art.

It will also be understood that when a layer is referred to as being“on” another layer or substrate, it can be directly on the other layeror substrate, or intervening layers may also be present. When an elementis referred to as being “directly on,” there are no intervening elementspresent. The same reference numbers indicate the same componentsthroughout the specification.

It will be understood that, although the terms “first,” “second,” etc.may be used herein to describe various elements, these elements shouldnot be limited by these terms. These terms are only used to distinguishone element from another element. For instance, a first elementdiscussed below could be termed a second element without departing fromthe spirit and scope of the present disclosure. Similarly, the secondelement could also be termed the first element.

As used herein, expressions such as “at least one of”, “one of”, and“selected from”, when preceding a list of elements, modify the entirelist of elements and do not modify the individual elements of the list.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items.

Further, the use of “may” when describing embodiments of the presentdisclosure refers to “one or more embodiments of the presentdisclosure.”

Hereinafter, embodiments of the present disclosure will be describedwith reference to the accompanying drawings.

FIG. 1 is a schematic plan view of a display device according to oneembodiment.

Referring to FIG. 1 , a display device 10 displays a moving image or astill image. The display device 10 may refer to any suitable electronicdevice which provides (includes) a display screen. For example, thedisplay device 10 may include televisions, notebooks (laptop computers),monitors, advertising boards, Internet of Things devices, mobile phones,smart phones, tablet personal computers (PCs), electronic clocks, smartwatches, watch phones, head mounted displays, mobile communicationterminals, electronic notebooks, electronic books, portable multimediaplayers (PMPs), navigation devices, game machines, digital cameras,camcorders, and/or the like, which provide (include) display screens.

The display device 10 includes a display panel including a displayscreen. Non-limiting examples of the display panel may include lightemitting diode (LED) display panels, organic light emitting displaypanels, quantum dot light emitting display panels, plasma displaypanels, field emission display panels, and the like. Hereinafter, a casein which the LED display panel is applied as an example of the displaypanel is illustrated, but the present disclosure is not limited thereto,and other suitable display panels may be applied as long assubstantially the same technical spirit is applicable.

A shape of the display device 10 may be variously suitably modified. Forexample, the display device 10 may have a rectangular shape having along width (e.g., where width is larger than each of length and height),a rectangular shape having a long height (e.g., where height is largerthan each of length and width), a square shape, a quadrangular shapehaving rounded corners, shape of other polygons, a circular shape,and/or the like. A shape of a display area DA of the display device 10may also be substantially similar to the shape of the display device 10.In FIG. 1 , the display device 10 and the display area DA, which areboth of a rectangular shape having a long width, are illustrated.

The display device 10 may include the display area DA and a non-displayarea NDA. The display area DA is an area in which a screen (image) maybe displayed, and the non-display area NDA is an area in which thescreen (image) is not displayed. The display area DA may be referred toas an active area, and the non-display area NDA may be referred to as aninactive area.

The display area DA may approximately occupy a center of the displaydevice 10. The display area DA may include a plurality of pixels PX. Theplurality of pixels PX may be arranged in row and column directions. Ina plan view, a shape of each pixel PX may be a rectangle or squareshape, but the present disclosure is not limited thereto. Each pixel PXmay have a rhombic shape in which each side thereof is inclined withrespect to one direction. Each pixel PX may include one or more lightemitting elements 300, which can emit light in a specific (e.g., set)wavelength range, to display a specific (e.g., set) color.

FIG. 2 is a schematic plan view of one pixel of the display deviceaccording to one embodiment. FIG. 3 is a plan view illustrating onesub-pixel of FIG. 2 .

Referring to FIGS. 2 and 3 , each of the plurality of pixels PX mayinclude a first sub-pixel PX1, a second sub-pixel PX2, and a thirdsub-pixel PX3. The first sub-pixel PX1 may emit light having a firstcolor, the second sub-pixel PX2 may emit light having a second color,and the third sub-pixel PX3 may emit light having a third color. Thefirst color may be a blue color, the second color may be a green color,and the third color may be a red color, but the present disclosure isnot limited thereto, and each sub-pixel PXn may emit light of the samecolor. Further, although each pixel PX including three sub-pixels PXnhas been illustrated in FIG. 2 , the present disclosure is not limitedthereto, and each pixel PX may include a greater number of sub-pixelsPXn (e.g., more than three sub-pixels PXn).

Each sub-pixel PXn of the display device 10 may include an area definedas a light emission area EMA. The first sub-pixel PX1 may include afirst light emission area EMA1, the second sub-pixel PX2 may include asecond light emission area EMA2, and the third sub-pixel PX3 may includea third emission area EMA3. The light emission area EMA may be definedas an area in which light emitting element 300 included in the displaydevice 10 is to emit light in a specific (e.g., set) wavelength range.The light emitting element 300 includes an active layer 330, and theactive layer 330 may emit light in a specific (e.g., set) wavelengthrange without any specific orientation. For example, the light emittedfrom the active layer 330 of the light emitting element 300 may beemitted in a side direction of the light emitting element 300 as well asin both end portion directions thereof. The light emission area EMA ofeach sub-pixel PXn may include an area in which the light emittingelement 300 is present. And, the light emission area EMA may furtherinclude an area in which the light from the light emitting element 300is emitted. However, the present disclosure is not limited thereto, andthe light emission area EMA may also include an area in which the lightemitted from the light emitting element 300 is reflected and/orrefracted due to another member to be emitted. A plurality of lightemitting elements 300 may be included in each sub-pixel PXn, and maytogether form the light emission area EMA including an area in which thelight emitting elements 300 are present and an area adjacent thereto.

In one or more embodiments, each sub-pixel PXn of the display device 10may include a non-light emission area, which may be defined as an areaof the sub-pixel PXn except for the light emission area EMA. Thenon-light emission area may be an area in which the light emittingelements 300 are not present and to which light emitted from the lightemitting elements 300 does not reach, so that light is not emitted inthe non-light emission area.

Each sub-pixel PXn of the display device 10 may include a plurality ofelectrodes 210 and 220, the light emitting elements 300, a plurality ofcontact electrodes 260, a plurality of banks 410, 420, and 430 shown inFIG. 4 , and one or more insulating layers 510, 520, and 550 (see FIG. 4).

The plurality of electrodes 210 and 220 may be electrically connected tothe light emitting elements 300 and may receive a predetermined (or set)voltage so as to allow the light emitting elements 300 to emit light ina specific (e.g., set) wavelength range. Further, at least a portion ofeach of the electrodes 210 and 220 may be utilized to form an electricfield in the sub-pixel PXn to align the light emitting elements 300.

The plurality of electrodes 210 and 220 may include a first electrode210 and a second electrode 220. In an exemplary embodiment, the firstelectrode 210 may be a pixel electrode, which is separated with respectto each sub-pixel PXn, and the second electrode 220 may be a commonelectrode, which is commonly connected along each sub-pixel PXn (e.g.,commonly connected across all sub-pixels PXn in one pixel PX). One ofthe first electrode 210 and the second electrode 220 may be an anodeelectrode of the light emitting element 300, and the other thereof maybe a cathode electrode of the light emitting element 300. However, thepresent disclosure is not limited thereto.

The first electrode 210 and the second electrode 220 may respectivelyinclude electrode stems 210S and 220S extending in a first directionDR1, and one or more electrode branches 210B and 220B extending andbranching from the electrode stem 210S and 220S in a second directionDR2 intersecting the first direction DR1.

The first electrode 210 may include a first electrode stem 210Sextending in the first direction DR1, and at least one first electrodebranch 210B branching from the first electrode stem 210S to extend inthe second direction DR2.

Both ends of a first electrode stem 210S of any one pixel may be formedto be spaced apart from each other between the sub-pixels PXn and to besubstantially collinear (e.g., substantially aligned) with a firstelectrode stem 210S of a sub-pixel PXn in the same row (e.g., adjacentthereto in the first direction DR1). Both ends of the first electrodestem 210S in each sub-pixel PXn may be spaced apart from each other sothat different electrical signals may be applied to the first electrodebranches 210B (if more than one are present), and the first electrodebranch 210B may be individually driven.

In one or more embodiments, the first electrode branch 210B branchesfrom at least a portion of the first electrode stem 210S and extends inthe second direction DR2. The first electrode branch 210B may be spacedapart from the second electrode stem 220S facing the first electrodestem 210S.

The second electrode 220 may include the second electrode stem 220S,which extends in the first direction DR1 and is spaced apart from thefirst electrode stem 210S in the second direction DR2 to face the firstelectrode stem 210S, and a second electrode branch 220B, which branchesfrom the second electrode stem 220S and extends in the second directionDR2. One end portion of the second electrode stem 220S may be connectedto a second electrode stem 220S of another sub-pixel PXn adjacentthereto in the first direction DR1. For example, unlike the firstelectrode stem 210S, the second electrode stem 220S may extend in thefirst direction DR1 to cross each sub-pixel PXn. The second electrodestem 220S crossing each sub-pixel PXn may be connected to an outerportion of the display area DA, in which each pixel PX or each sub-pixelPXn is positioned, or connected to a portion extending from thenon-display area NDA in one direction.

The second electrode branch 220B may be spaced apart from and may facethe first electrode branch 210B in the first direction DR1. The secondelectrode branch 220B may be spaced apart from the first electrode stem210S in the second direction DR2. The second electrode branch 220B maybe connected to the second electrode stem 220S, and an end portion ofthe second electrode branch 220B in an extension direction thereof(e.g., in the second direction DR2) may be positioned in the sub-pixelPXn and may be spaced apart from the first electrode stem 210S.

The first electrode 210 and the second electrode 220 may each beelectrically connected to a circuit element layer PAL (see FIG. 22 ) ofthe display device 10 through contact holes, e.g., a first electrodecontact hole CNTD and a second electrode contact hole CNTS. In thedrawings, the first electrode contact hole CNTD has been illustrated asbeing formed in the first electrode stem 210S of each sub-pixel PXn, andone second electrode contact hole CNTS has been illustrated as beingformed in one second electrode stem 220S crossing each sub-pixel PXn(e.g., the one second electrode contact hole CNTS may be formed in onlyone sub-pixel PXn). However, the present disclosure is not limitedthereto, and in some cases, the second electrode contact hole CNTS maybe formed in each sub-pixel PXn.

In the drawings, two first electrode branches 210B have been illustratedas being on each sub-pixel PXn, and one second electrode branch 220B hasbeen illustrated as being between the two first electrode branch 210B,but the present disclosure is not limited thereto. Further, the firstelectrode 210 and the second electrode 220 do not necessarily have ashape extending in one direction and may have various suitablestructures. For example, the first electrode 210 and the secondelectrode 220 may have a partially curved or bent shape, and oneelectrode of the first electrode 210 and the second electrode 220 maysurround the other electrode thereof. A structure or shape of the firstelectrode 210 and the second electrode 220 may not be particularlylimited as long as at least some regions of the first electrode 210 andthe second electrode 220 are spaced apart from and face each other toform a space in which the light emitting element 300 will be placedbetween the at least some regions thereof.

Further, in some embodiments, the electrode stem 210S and 220S may berespectively omitted from the first electrode 210 and the secondelectrode 220. The first electrode 210 and the second electrode 220 mayhave a shape extending in only one direction and may be spaced apartfrom each other in each sub-pixel PXn. A description thereof will bemade herein with reference to another embodiment.

The plurality of banks 410, 420, and 430 may include an outer bank 430at a boundary between the sub-pixels PXn, and a plurality of inner banks410 and 420 below the electrode 210 and 220 adjacent to a center of eachsub-pixel PXn. In one or more embodiments, a first inner bank 410 and asecond inner bank 420 may be respectively below the first electrodebranch 210B and the second electrode branch 220B.

The outer bank 430 may be at the boundary between the sub-pixels PXn.End portions of the plurality of first electrode stems 210S may beformed to be spaced apart from each other based on the outer bank 430.The outer bank 430 may extend in the second direction DR2 and may bepositioned at the boundary between each two adjacent the sub-pixels PXnalong the first direction DR1. However, the present disclosure is notlimited thereto, and the outer bank 430 may extend in the firstdirection DR1 and may be positioned at a boundary between each twoadjacent sub-pixels PXn along the second direction DR2. The outer bank430 may include the same material as each of the inner banks 410 and 420and may be simultaneously (or concurrently) formed with the inner banks410 and 420 in a single process.

The light emitting element 300 may be between the first electrode 210and the second electrode 220. One end portion of the light emittingelement 300 may be electrically connected to the first electrode 210,and the other end portion thereof may be electrically connected to thesecond electrode 220. The light emitting element 300 may be electricallyconnected to the first electrode 210 and the second electrode 220through the contact electrodes 260 which will be described below.

A plurality of light emitting elements 300 may be spaced apart from eachother and arranged substantially in parallel. A separation distancebetween the light emitting elements 300 is not particularly limited. Insome cases, the plurality of light emitting elements 300 may be adjacentto each other to form a group, and a plurality of other light emittingelements 300 may be grouped in a state of being spaced at regularintervals and may have a nonuniform density but may be oriented in onedirection to be arranged. Further, in an embodiment, the light emittingelement 300 may have a shape extending in one direction, and a directionin which each electrode, e.g., each of the first electrode branch 210Band the second electrode branch 220B, extends may be substantiallyperpendicular to (e.g., may cross) a direction in which the lightemitting element 300 extends. However, the present disclosure is notlimited thereto, and the light emitting element 300 may be obliquelypositioned without being perpendicular to the direction in which thefirst electrode branch 210B and the second electrode branch 220B extend.

The light emitting elements 300 according to one embodiment may includeactive layers 330 having different materials to emit light in differentwavelength ranges to the outside. The display device 10 according to oneembodiment may include light emitting elements 300 for emitting light indifferent wavelength ranges. The display device 10 may include the lightemitting elements 300 in each sub-pixel PXn; the light emitting elements300 may have the same structure and may include active layers 330 foremitting light in different wavelength ranges. The light emittingelement 300 of the first sub-pixel PX1 may include an active layer 330which emits a first light L1 having a first wavelength at a centralwavelength range, the light emitting element 300 of the second sub-pixelPX2 may include an active layer 330 which emits s second light L2 havinga second wavelength at a central wavelength range, and the lightemitting element 300 of the third sub-pixel PX3 may include an activelayer 330 which emits s third light L3 having a third wavelength at acentral wavelength range.

Thus, the first light L1 may be emitted from the first sub-pixel PX1,the second light L2 may be emitted from the second sub-pixel PX2, andthe third light L3 may be emitted from the third sub-pixel PX3. In someembodiments, the first light L1 may be blue light in a centralwavelength range of 450 nm to 495 nm, the second light L2 may be greenlight in a central wavelength range of 495 nm to 570 nm, and the thirdlight L3 may be red light in a central wavelength range of 620 nm to 752nm.

However, the present disclosure is not limited thereto. The first lightL1, the second light L2, and the third light L3 may have colorsdifferent from those described above, or may have the same color, butthe central wavelength ranges may be different from the above-describedranges. Further, in some cases, the first sub-pixel PX1, the secondsub-pixel PX2, and the third sub-pixel PX3 may include the same type (orkind) of light emitting elements 300 to emit light having thesubstantially same color.

In one or more embodiments, the display device 10 may include the firstinsulating layer 510 which covers at least portions of the firstelectrode 210 and the second electrode 220.

The first insulating layer 510 may be in each sub-pixel PXn of thedisplay device 10. The first insulating layer 510 may substantiallycover an entirety of each sub-pixel PXn and may extend even to otheradjacent sub-pixels PXn. The first insulating layer 510 may cover atleast portions of the first electrode 210 and the second electrode 220.In some embodiments, the first insulating layer 510 may expose someportions of the first electrode 210 and the second electrode 220, forexample, some portions of the first electrode branch 210B and the secondelectrode branch 220B.

The plurality of contact electrodes 260 may have a shape extending inone direction. Each of the plurality of contact electrodes 260 may be incontact with the light emitting element 300 and the electrodes 210 and220, and the light emitting elements 300 may receive an electricalsignal from the first electrode 210 and the second electrode 220 throughthe contact electrodes 260.

The contact electrode 260 may include a first contact electrode 261 anda second contact electrode 262. The first contact electrode 261 and thesecond contact electrode 262 may be respectively on the first electrodebranch 210B and the second electrode branch 220B.

The first contact electrode 261 may be on the first electrode 210 or thefirst electrode branch 210B, to extend in the second direction DR2, andmay be in contact with one end portion of the light emitting element300. The second contact electrode 262 may be on the second electrode 220or the second electrode branch 220B, to extend in the second directionDR2, and may be in contact with the other end portion of the lightemitting element 300. As described below, the first contact electrode261 and the second contact electrode 262 may be in contact with thefirst electrode 210 and the second electrode 220 which are exposedthrough an opening of the first insulating layer 510. The light emittingelement 300 may be electrically connected to the first electrode 210 andthe second electrode 220 through the first contact electrode 261 and thesecond contact electrode 262.

In some embodiments, the first contact electrode 261 and the secondcontact electrode 262 may each have a larger width, measured in onedirection, than the widths of each of the first electrode 210 and thesecond electrode 220 (or the first electrode branch 210B and the secondelectrode branch 220B), measured in the one direction. The first contactelectrode 261 and the second contact electrode 262 may respectivelycover side portions of the first electrode 210 and the second electrode220 (or the first electrode branch 210B and the second electrode branch220B). However, the present disclosure is not limited thereto, and insome cases, the first contact electrode 261 and the second contactelectrode 262 may respectively cover only one side portion of the firstelectrode branch 210B and the second electrode branch 220B.

Although two first contact electrodes 261 and one second contactelectrode 262 have been illustrated in one sub-pixel PXn in thedrawings, the present disclosure is not limited thereto. The number ofthe first contact electrodes 261 and the second contact electrodes 262may be varied according to the number of the first electrodes 210 andthe second electrodes 220, or the number of the first electrode branch210B and the second electrode branch 220B, which are included in eachsub-pixel PXn.

In one or more embodiments, a second insulating layer 520 (see FIG. 4 )is positioned on an outer surface of the light emitting element 300. Thesecond insulating layer 520 may be formed to partially surround theouter surface of the light emitting element 300, and may serve toprotect and, simultaneously (or concurrently), fix (affix) the lightemitting element 300.

The display device 10 according to one embodiment may include aplurality of insulating patterns 510P, 521, and 522. In addition to thefirst insulating layer 510 and the second insulating layer 520, thedisplay device 10 may include more insulating layers. Among theinsulating layers, the first insulating layer 510 may include a firstinsulating pattern 510P (see FIG. 4 ) located between the firstelectrode 210 and the second electrode 220, and the second insulatinglayer 520 may include a second insulating pattern 521 on the lightemitting element 300. Although only the second insulating pattern 521 ofthe second insulating layer 520 has been illustrated in FIGS. 2 and 3 ,the present disclosure is not limited thereto.

The second insulating pattern 521 may extend in the second direction DR2between the first electrode 210 and the second electrode 220. At least aportion of the second insulating pattern 521 may be on the lightemitting element 300, and another portion thereof may be on a via layer200 (see FIG. 4 ). Further, the second insulating pattern 521 may bebetween the first contact electrode 261 and the second contact electrode262. A process of forming the contact electrodes 261 and 262 in afabricating method of the display device 10 may be performed by a liftoff process. Due to the lift-off process, the contact electrodes 261 and262 may not be positioned on the second insulating layer 520, e.g., onan upper surface of the second insulating pattern 521, and the secondinsulating pattern 521 may include a contact surface in contact with thecontact electrodes 261 and 262. According to one embodiment, a contactsurface on which the second insulating pattern 521 is in contact withthe contact electrodes 261 and 262 may not be parallel to the uppersurface of the second insulating pattern 521. A more detaileddescription thereof will be made below with reference to other drawings.

In addition to the first insulating layer 510, the display device 10 mayinclude the circuit element layer PAL below each of the electrodes 210and 220, the second insulating layer 520 covering at least a portion ofeach of the electrodes 210 and 220 and the light emitting element 300,and a passivation layer 550 (see FIG. 4 ). Hereinafter, the structure ofthe display device 10 will be described in more detail with reference toFIG. 4 .

FIG. 4 shows cross-sectional views taken along lines Xa-Xa′, Xb-Xb′, andXc-Xc′ of FIG. 3 .

FIG. 4 shows the cross-sectional views of the first sub-pixel PX1 butmay be similarly applied to another pixel PX or sub-pixel PXn. FIG. 4shows the cross-sectional sectional views from one end portion to theother end portion of the light emitting element 300 in the firstsub-pixel PX1.

Referring to FIG. 4 , with reference to FIGS. 2 and 3 , the displaydevice 10 may include the circuit element layer PAL and a light emittinglayer EML. The circuit element layer PAL may include a substrate 110, abuffer layer 115, a light blocking layer BML, and first and secondtransistors 120 and 140; and the light emitting layer EML may includethe plurality of electrodes 210 and 220, the light emitting element 300,and the plurality of insulating layers 510, 520, and 550, which arepositioned on the first and second transistors 120 and 140.

The substrate 110 may be an insulating substrate. The substrate 110 maybe made of an insulating material such as glass, quartz, a polymerresin, and/or the like. The substrate 110 may be a rigid substrate or aflexible substrate which is bendable, foldable, rollable, and/or thelike.

The light blocking layer BML may be on the substrate 110. The lightblocking layer BML may include a first light blocking layer BML1 and asecond light blocking layer BML2. The first light blocking layer BML1may be electrically connected to a first drain electrode 123 of thefirst transistor 120, which will be described below. The second lightblocking layer BML2 may be electrically connected to a second drainelectrode 143 of the second transistor 140.

The first light blocking layer BML1 and the second light blocking layerBML2 are respectively positioned to overlap a first active materiallayer 126 of the first transistor 120 and a second active material layer146 of the second transistor 140. The first and second light blockinglayers BML1 and BML2 may include light blocking materials to prevent (orreduce) light from being incident on the first and second activematerial layers 126 and 146. For example, the first and second lightblocking layers BML1 and BML2 may be formed of opaque metal materialswhich block (or reduce) light transmission. However, the presentdisclosure is not limited thereto, and in some cases, the light blockinglayer BML may be omitted.

The buffer layer 115 may be on the light blocking layer BML and thesubstrate 110. The buffer layer 115 may cover an entirety of thesubstrate 110 including the light blocking layer BML. The buffer layer115 may prevent (or reduce) diffusion of impurity ions and infiltrationof water and/or outdoor air, and may perform a surface planarizationfunction. Further, the buffer layer 115 may insulate the light blockinglayer BML from the first and second active material layers 126 and 146.

A semiconductor layer may be on the buffer layer 115. The semiconductorlayer may include the first active material layer 126 of the firsttransistor 120, the second active material layer 146 of the secondtransistor 140, and an auxiliary layer 163. The semiconductor layer mayinclude polycrystalline silicon, single crystalline silicon, an oxidesemiconductor, and/or the like.

The first active material layer 126 may include a first doped region 126a, a second doped region 126 b, and a first channel region 126 c. Thefirst channel region 126 c may be between the first doped region 126 aand the second doped region 126 b. The second active material layer 146may include a third doped region 146 a, a fourth doped region 146 b, anda second channel region 146 c. The second channel region 146 c may bebetween the third doped region 146 a and the fourth doped region 146 b.The first active material layer 126 and the second active material layer146 may each independently include polycrystalline silicon. Thepolycrystalline silicon may be formed by crystallizing amorphoussilicon. Examples of the crystallization method may include a rapidthermal annealing (RTA) method, a solid phase crystallization (SPC)method, an excimer laser annealing (ELA) method, a metal inducedcrystallization (MILC) method, a sequential lateral solidification (SLS)method, and the like, but the present disclosure is not limited thereto.In some embodiments, the first active material layer 126 and the secondactive material layer 146 may include single crystalline silicon, lowtemperature polycrystalline silicon, amorphous silicon, and/or the like.The first doped region 126 a, the second doped region 126 b, the thirddoped region 146 a, and the fourth doped region 146 b may be regions ofthe first active material layer 126 and the second active material layer146 that are doped with impurities. However, the present disclosure isnot limited thereto.

The first active material layer 126 and the second active material layer146 are not necessarily limited to the above description. In anembodiment, the first active material layer 126 and the second activematerial layer 146 may each independently include an oxidesemiconductor. In this case, the first doped region 126 a and the thirddoped region 146 a may be first conductorized regions (e.g., regionshaving electrical conductivity or regions in which the electricalconductivity has been increased), and the second doped region 126 b andthe fourth doped region 146 b may be second conductorized regions. Whenthe first active material layer 126 and the second active material layer146 include an oxide semiconductor, the oxide semiconductor may be anoxide semiconductor containing indium (In). In some embodiments, theoxide semiconductor may include indium-tin oxide (ITO), indium-zincoxide (IZO), indium-gallium oxide (IGO), indium-zinc-tin oxide (IZTO),indium-gallium-tin oxide (IGTO), indium-gallium-zinc-tin oxide (IGZTO),and/or the like. However, the present disclosure is not limited thereto.

A first gate insulating layer 150 may be on the semiconductor layer. Thefirst gate insulating layer 150 may cover an entirety of the bufferlayer 115 including the semiconductor layer. The first gate insulatinglayer 150 may serve as a gate insulating layer of the first and secondtransistors 120 and 140.

A first conductive layer may be on the first gate insulating layer 150.On the first gate insulating layer 150, the first conductive layer mayinclude a first gate electrode 121 on the first active material layer126 of the first transistor 120, a second gate electrode 141 on thesecond active material layer 146 of the second transistor 140, and apower line 161 on the auxiliary layer 163. The first gate electrode 121may overlap the first channel region 126 c of the first active materiallayer 126, and the second gate electrode 141 may overlap the secondchannel region 146 c of the second active material layer 146.

An interlayer insulating layer 170 may be on the first conductive layer.The interlayer insulating layer 170 may serve as an insulating layerbetween the first conductive layer and other layers thereabove. Theinterlayer insulating layer 170 may include an organic insulatingmaterial and may perform a surface planarization function.

A second conductive layer may be on the interlayer insulating layer 170.The second conductive layer includes the first drain electrode 123 and afirst source electrode 124 of the first transistor 120, the second drainelectrode 143 and a second source electrode 144 of the second transistor140, and a power electrode 162 on the power line 161.

The first drain electrode 123 and the first source electrode 124 may berespectively in contact with the first doped region 126 a and the seconddoped region 126 b of the first active material layer 126 throughcontact holes passing through the interlayer insulating layer 170 andthe first gate insulating layer 150. The second drain electrode 143 andthe second source electrode 144 may be respectively in contact with thethird doped region 146 a and the fourth doped region 146 b of the secondactive material layer 146 through contact holes passing through theinterlayer insulating layer 170 and the first gate insulating layer 150.Further, the first drain electrode 123 and the second drain electrode143 may be electrically connected to the first light blocking layer BML1and the second light blocking layer BML2 through other contact holes.

The via layer 200 may be on the second conductive layer. The via layer200 may include an organic insulating material and may perform a surfaceplanarization function.

The plurality of banks 410, 420, and 430, the plurality of electrodes210 and 220, and the light emitting element 300 may be on the via layer200.

The plurality of banks 410, 420, and 430 may include inner banks 410 and420 spaced apart from each other in each sub-pixel PXn, and an outerbank 430 on a boundary of a sub-pixel PXn adjacent thereto.

As described above, the outer bank 430 may extend in the first directionDR1 or the second direction DR2 and may be positioned at a boundarybetween each two adjacent sub-pixels PXn. For example, the outer bank430 may divide (define) the boundary of each sub-pixel PXn.

During fabrication of the display device 10, when an ink in which thelight emitting elements 300 are distributed is injected using an inkjetprinting device, the outer bank 430 may perform a function of preventing(or reducing) the ink from crossing the boundary of the sub-pixel PXn.The outer bank 430 may separate inks in which different light emittingelements 300 are distributed from each other in different sub-pixels PXnso as to prevent (or reduce) the inks from being mixed with each other.However, the present disclosure is not limited thereto.

The plurality of inner banks 410 and 420 may include a first inner bank410 and a second inner bank 420 which are positioned adjacent to acenter of each sub-pixel PXn.

The first inner bank 410 and the second inner bank 420 may be spacedapart from and may face each other. The first electrode 210 may be onthe first inner bank 410, and the second electrode 220 may be on thesecond inner bank 420. Referring to FIGS. 3 and 4 , it can be understoodthat the first electrode branch 210B is on the first inner bank 410, andthe second electrode branch 220B is on the second inner bank 420.

The first inner bank 410 and the second inner bank 420 may extend in thesecond direction DR2 in each sub-pixel PXn. Because the first inner bank410 and the second inner bank 420 extend in the second direction DR2,the first inner bank 410 and the second inner bank 420 may extend towarda sub-pixel PXn adjacent thereto in the second direction DR2. However,the present disclosure is not limited thereto, and the first inner bank410 and the second inner bank 420 may be positioned in each sub-pixelPXn to form a pattern. The plurality of banks 410, 420, and 430 may eachindependently include polyimide (PI), but the present disclosure is notlimited thereto.

The first inner bank 410 and the second inner bank 420 may have astructure in which at least portions thereof partially protrude withrespect to the via layer 200. The first inner bank 410 and the secondinner bank 420 may protrude upward from a surface on which the lightemitting element 300 is positioned, and at least portions of theprotruding portions may have an inclination. The protruding shapes ofthe first inner bank 410 and the second inner bank 420 are notparticularly limited. Because the inner banks 410 and 420 have inclinedside surfaces protruding from the via layer 200, light emitted from thelight emitting element 300 may be reflected from the inclined sidesurfaces of the inner banks 410 and 420. As described below, when theelectrodes 210 and 220 on the inner banks 410 and 420 include a materialhaving high reflectance, the light emitted from the light emittingelement 300 may be reflected from the electrodes 210 and 220, which arelocated on the inclined side surfaces of the inner banks 410 and 420, totravel in an upward direction of the via layer 200.

In one or more embodiments, the outer bank 430 may divide adjacentsub-pixels PXn and, simultaneously (or concurrently), may perform afunction of preventing (or reducing) an ink from overflowing to adjacentsub-pixels PXn in the inkjet process; whereas, the inner banks 410 and420 may have a protruding structure in each sub-pixel PXn to serve as areflective partition wall, which reflects the light emitted from thelight emitting element 300 in the upward direction of the via layer 200.However, the present disclosure is not limited thereto.

The plurality of electrodes 210 and 220 may be on the via layer 200 andthe inner banks 410 and 420. The electrodes 210 and 220 may respectivelyinclude the electrode stem 210S and 220S and the electrode branch 210Band 220B. In FIG. 3 , line Xa-Xa′ is a line crossing the first electrodestem 210S, line Xb-Xb′ is a line crossing the first electrode branch210B and the second electrode branch 220B, and line Xc-Xc′ is a linecrossing the second electrode stem 220S. For example, in FIG. 4 , thefirst electrode 210 in area Xa-Xa′ is the first electrode stem 210S, thefirst electrode 210 and the second electrode 220 in area Xb-Xb′ arerespectively the first electrode branch 210B and the second electrodebranch 220B, and the second electrode 220 in area Xc-Xc′ is the secondelectrode stem 220S.

Some areas of the first electrode 210 and the second electrode 220 maybe on the via layer 200, and some areas thereof may be on the firstinner bank 410 and the second inner bank 420. For example, the widths ofthe first electrode 210 and the second electrode 220, measured in thefirst direction DR1, may each be greater than those of the inner banks410 and 420. Some portions of lower surfaces of the first electrode 210and the second electrode 220 may be in contact with the via layer 200,and some other portions thereof may be in contact with the inner banks410 and 420.

Further, the first electrode stem 210S and the second electrode stem220S may extend in the first direction DR1, and the first inner bank 410and the second inner bank 420 may extend in the second direction DR2,such that the first electrode stem 210S, the second electrode stem 220S,the first inner bank 410, and the second inner bank 420 may cross theboundary of the sub-pixel PXn. The first electrode stem 210S and thesecond electrode stem 220S may partially overlap the first inner bank410 and the second inner bank 420. However, the present disclosure isnot limited thereto, and, as shown in the drawings, the first electrodestem 210S and the second electrode stem 220S may not overlap the firstinner bank 410 and the second inner bank 420.

The first electrode contact hole CNTD may be formed in the firstelectrode stem 210S to partially expose the first drain electrode 123 ofthe first transistor 120 by passing through the via layer 200. The firstelectrode 210 may be in contact with the first drain electrode 123through the first electrode contact hole CNTD. The first electrode 210may be electrically connected to the first drain electrode 123 of thefirst transistor 120 to receive a predetermined (or set) electricalsignal therefrom.

The second electrode contact hole CNTS may be formed in the secondelectrode stem 220S to partially expose the power electrode 162 bypassing through the via layer 200. The second electrode 220 may be incontact with the power electrode 162 through the second electrodecontact hole CNTS. The second electrode 220 may be electricallyconnected to the power electrode 162 to receive a predetermined (or set)electrical signal therefrom.

Some regions of the first electrode 210 and the second electrode 220,e.g., the first electrode branch 210B and the second electrode branch220B, may be respectively on the first inner bank 410 and the secondinner bank 420. The first electrode branch 210B may cover the firstinner bank 410, and the second electrode branch 220B may cover thesecond inner bank 420. The first electrode branch 210B and the secondelectrode branch 220B may be spaced apart from each other, and theplurality of light emitting elements 300 may be between the firstelectrode branch 210B and the second electrode branch 220B.

Each of the electrodes 210 and 220 may include a transparent conductivematerial. For example, each of the electrodes 210 and 220 may include amaterial such as ITO, IZO, indium-tin-zinc oxide (ITZO), and/or thelike, but the present disclosure is not limited thereto. In someembodiments, each of the electrodes 210 and 220 may include a conductivematerial having high reflectance. For example, each of the electrodes210 and 220 may include a metal such as silver (Ag), copper (Cu),aluminum (Al), and/or the like, as a material having high reflectance.In this case, light incident on each of the electrodes 210 and 220 maybe reflected and emitted in the upward direction of each sub-pixel PXn.

Further, each of the electrodes 210 and 220 may be formed in astructure, in which one or more layers of a transparent conductivematerial and a metal layer having high reflectance are stacked, orformed of a single layer including the transparent conductive materialand the metal layer. In an embodiment, each of the electrodes 210 and220 may have a stacked structure of ITO/Ag/ITO/IZO or may be an alloycontaining Al, nickel (Ni), lanthanum (La), and/or the like. However,the present disclosure is not limited thereto.

The first insulating layer 510 may on the via layer 200, the firstelectrode 210, and the second electrode 220. The first insulating layer510 partially cover the first electrode 210 and the second electrode220. Openings OP1 and OP2 (see FIG. 11 ) may be formed in the firstinsulating layer 510, and some portions of the first electrode 210 andthe second electrode 220 may be exposed through the openings OP1 andOP2. The openings of the first insulating layer 510 may be located toexpose relatively flat upper surfaces of the first electrode 210 and thesecond electrode 220.

In an embodiment, a step may be formed in the first insulating layer 510between the first electrode 210 and the second electrode 220 so as torecess an upper surface of the first insulating layer 510. In someembodiments, the first insulating layer 510 may include an inorganicinsulating material, and a portion of the upper surface of the firstinsulating layer 510, which covers the first electrode 210 and thesecond electrode 220, may be recessed due to a step of a memberpositioned below the first insulating layer 510. The light emittingelement 300 on the first insulating layer 510 between the firstelectrode 210 and the second electrode 220 may be formed in an emptyspace between the recessed upper surfaces of the first insulating layer510. The light emitting element 300 may be partially spaced apart fromthe upper surface of the first insulating layer 510, and the empty spacemay be filled with a material for forming the second insulating layer520, which will be described in more detail below.

However, the present disclosure is not limited thereto. The firstinsulating layer 510 may form a substantially flat upper surface so asto allow the light emitting element 300 to be positioned on it. Thesubstantially flat upper surface may be formed to extend to the inclinedside surfaces of the first electrode 210 and the second electrode 220 inone direction toward the first electrode 210 and the second electrode220. For example, the first insulating layer 510 may be in a region inwhich the electrodes 210 and 220 overlap the inclined side surfaces ofthe first inner bank 410 and the second inner bank 420. The contactelectrode 260 may be in contact with the exposed regions of the firstelectrode 210 and the second electrode 220 and may be in contact with anend portion of the light emitting element 300 on the substantially flatupper surface of the first insulating layer 510.

The first insulating layer 510 may protect the first electrode 210 andthe second electrode 220 and, simultaneously (or concurrently), mayinsulate the first electrode 210 from the second electrode 220. Further,the light emitting element 300 on the first insulating layer 510 may beprevented (or protected) from being damaged by being in direct contactwith other members. However, the shape and structure of the firstinsulating layer 510 is not limited thereto.

The light emitting element 300 may be on the first insulating layer 510between the electrodes 210 and 220. At least one light emitting element300 may be on the first insulating layer 510. However, the presentdisclosure is not limited thereto, and, in some embodiments, at leastsome of the light emitting elements 300 in each sub-pixel PXn may be ina region other than a region between the electrode branch 210B and 220B.For example, in some embodiments, at least some of the light elements300 in each sub-pixel PXn are not in the region between the electrodebranch 210B and 220B. Further, the light emitting element 300 may bepositioned in a region that overlaps the electrodes 210 and 220. Thelight emitting element 300 may be on end portions of the first electrodebranch 210B and the second electrode branch 220B facing each other.

The light emitting element 300 may include a plurality of layersarranged in a direction parallel to the via layer 200 (e.g., along theextension direction of the via layer 200). The light emitting element300 of the display device 10 according to one embodiment may have ashape extending in one direction, and have a structure in which aplurality of semiconductor layers are sequentially positioned in the onedirection. As described in more detail below, in the light emittingelement 300, a first semiconductor layer 310, the active layer 330, asecond semiconductor layer 320, and an electrode layer 370 may besequentially positioned in the one direction, and an insulating layer380 may surround outer surfaces of the first semiconductor layer 310,the active layer 330, the second semiconductor layer 320, and theelectrode layer 370. The light emitting element 300 on the displaydevice 10 may be positioned such that the one direction for extensionthereof is parallel to the via layer 200 (e.g., to the extensiondirection of the via layer 200), and the plurality of semiconductorlayers included in the light emitting element 300 may be sequentiallyarranged in a direction parallel to an upper surface of the via layer200. However, the present disclosure is not limited thereto. In somecases, when the light emitting element 300 has another structure, theplurality of semiconductor layers may be arranged in a directioncrossing (e.g., perpendicular) to the via layer 200.

Further, according to one embodiment, since the insulating layer 380 isnot formed on end surfaces of the light emitting element 300 in the onedirection, and the end surfaces thereof are exposed, the exposed endsurfaces may be in contact with the first contact electrode 261 and thesecond contact electrode 262, which will be described below in moredetail. However, the present disclosure is not limited thereto. Forexample, at least a portion of the insulating layer 380 on the lightemitting element 300 may be removed, and thus side surfaces of both endportions of the light emitting element 300 may be partially exposed dueto the removal of the insulating layer 380. In forming the secondinsulating layer 520 covering the outer surface of the light emittingelement 300 during the process of fabricating the display device 10, theinsulating layer 380 may be partially removed. The exposed side surfacesof the light emitting element 300 may be in contact with the firstcontact electrode 261 and the second contact electrode 262. However, thepresent disclosure is not limited thereto.

The second insulating layer 520 may be between the first electrode 210and the second electrode 220. The second insulating layer 520 maypartially surround the outer surface of the light emitting element 300.The second insulating layer 520 may protect the light emitting element300 and, simultaneously (or concurrently), may perform a function offixing (affixing) the light emitting element 300 during the process offabricating the display device 10. Further, in an embodiment, a portionof the material of the second insulating layer 520 may be between alower surface of the light emitting element 300 and the first insulatinglayer 510. The second insulating layer 520 may be formed to fill thespace between the first insulating layer 510 and the light emittingelement 300, which is formed during the process of fabricating thedisplay device 10. However, the present disclosure is not limitedthereto.

The display device 10 may include the plurality of insulating patterns.In an embodiment, the first insulating layer 510 may include the firstinsulating pattern 510P located between the first electrode 210 and thesecond electrode 220, and the second insulating layer 520 may includethe second insulating pattern 521 on the light emitting element 300 andthe third insulating pattern 522 between the light emitting element 300and the first insulating pattern 510P. The first insulating pattern 510Pmay be located between the openings OP1 and OP2 of the first insulatinglayer 510 and may be a in a region in which the light emitting element300 is positioned between the first electrode 210 and the secondelectrode 220. The second insulating pattern 521 of the secondinsulating layer 520 may be a portion surrounding the outer surface ofthe light emitting element 300, and the third insulating pattern 522 ofthe second insulating layer 520 may be on a portion of the firstinsulating pattern 510P that is partially recessed to fill the spaceformed between the light emitting elements 300.

Because the first insulating pattern 510P, the second insulating pattern521, and the third insulating pattern 522 are between the firstelectrode 210 and the second electrode 220, each of the first insulatingpattern 510P, the second insulating pattern 521, and the thirdinsulating pattern 522 may extend in the second direction DR2. Theplurality of insulating patterns 510P, 521, and 522 may be in contactwith the light emitting elements 300, the electrodes 210 and 220, andthe contact electrodes 261 and 262 to form a plurality of contactsurfaces. A more detailed description of the insulating patterns will bemade below with reference to other drawings.

The first contact electrode 261 and the second contact electrode 262 arerespectively on the electrodes 210 and 220. The second insulating layer520 may be between the first contact electrode 261 and the secondcontact electrode 262 and may insulate the first contact electrode 261from the second contact electrode 262 so as to prevent (or protect) thefirst contact electrode 261 and the second contact electrode 262 frombeing in direct contact with each other.

The first contact electrode 261 and the second contact electrode 262 maybe in contact with at least one end portion of the light emittingelement 300 and may be electrically connected to the first electrode 210or the second electrode 220 to receive an electrical signal.

The first contact electrode 261 may be in contact with the exposedregion of the first electrode 210 on the first inner bank 410, and thesecond contact electrode 262 may be in contact with the exposed regionof the second electrode 220 on the second inner bank 420. The firstcontact electrode 261 and the second contact electrode 262 may transmitelectrical signals, which are transmitted from the electrodes 210 and220 to the light emitting element 300.

The contact electrode 260 may include a conductive material. Forexample, the contact electrode 260 may include ITO, IZO, ITZO, Al,and/or the like. However, the present disclosure is not limited thereto.

The passivation layer 550 may be on the contact electrode 260 and thesecond insulating layer 520. The passivation layer 550 may serve toprotect members on the via layer 200 from an external environment.

Each of the first insulating layer 510, the second insulating layer 520,and the passivation layer 550, which are described above, may include aninorganic insulating material and/or an organic insulating material. Inan embodiment, the first insulating layer 510, the second insulatinglayer 520, and the passivation layer 550 may each independently includean inorganic insulating material such as silicon oxide (SiO_(x)),silicon nitride (SiN_(x)), silicon oxynitride (SiO_(x)N_(y)), aluminumoxide (Al₂O₃), aluminum nitride (AlN), and/or the like. Further, thefirst insulating layer 510, the second insulating layer 520, and thepassivation layer 550 may each independently include acrylic resin,epoxy resin, phenol resin, polyamide resin, polyimide resin, unsaturatedpolyester resin, polyphenylene resin, polyphenylene sulfide resin,benzocyclobutene, cardo resin, siloxane resin, silsesquioxane resin,polymethylmethacrylate, polycarbonate,polymethylmethacrylate-polycarbonate synthetic resin, and/or the like,as an organic insulating material. However, the present disclosure isnot limited thereto.

FIG. 5 is a cross-sectional view illustrating a portion of thecross-sectional view taken along line Xb-Xb′ of FIG. 4 . FIG. 6 is across-sectional view taken along line Xd-Xd′ of FIG. 3 .

FIG. 5 is a cross section crossing both end portions (e.g., from one endportion to the other) of the light emitting element 300 between thefirst electrode 210 and the second electrode 220, and FIG. 6 is a crosssection crossing a region in which the light emitting element 300 is notlocated between the first electrode 210 and the second electrode 220.

Referring to FIGS. 5 and 6 , the display device 10 may include theplurality of insulating layers 510, 520, and 550, and some of theinsulating layers 510, 520, and 550 may include the insulating patterns510P, 521, and 522. The first insulating layer 510 may include the firstinsulating pattern 510P, and the second insulating layer 520 may includethe second insulating pattern 521 and the third insulating pattern 522.

The first insulating layer 510 includes the first insulating pattern510P. The first insulating pattern 510P may be between and may partiallyoverlap the first electrode 210 and the second electrode 220. The firstinsulating pattern 510P may cover portions of the first electrode 210and the second electrode 220, which are on the via layer 200, andportions of the first electrode 210 and the second electrode 220, whichare inclined on the inner banks 410 and 420. Further, the firstinsulating pattern 510P may be in contact with the via layer 200 in aregion in which the first electrode 210 is spaced apart from the secondelectrode 220. Since the first insulating pattern 510P is in contactwith the first electrode 210, the second electrode 220, and the vialayer 200, a step may be formed on an upper surface of the firstinsulating pattern 510P, and a space may be formed between the firstinsulating pattern 510P and the light emitting element 300 positioned onthe upper surface of the first insulating pattern 510P. The thirdinsulating pattern 522 may be positioned in the formed space.

During the process of fabricating the display device 10, the firstinsulating layer 510 may be placed to cover the first electrode 210 andthe second electrode 220 on the via layer 200, and then the openings OP1and OP2 (see FIG. 11 ) may be formed so as to expose the first electrode210 and the second electrode 220. The first insulating pattern 510P is aportion in which the openings OP1 and OP2 are not formed in the firstinsulating layer 510, and the light emitting element 300 may be on thefirst insulating pattern 510P. In an embodiment, a width W4, measured inthe first direction DR1, of the first insulating pattern 510P may begreater than a length W1, measured in the first direction DR1, of thelight emitting element 300. Further, the width W4 of the firstinsulating pattern 510P may be greater than a gap between the firstelectrode 210 and the second electrode 220. However, the presentdisclosure is not limited thereto.

The second insulating layer 520 may include the second insulatingpattern 521 and the third insulating pattern 522. The second insulatingpattern 521 may be on the light emitting element 300 and may be formedto partially surround the outer surface of the light emitting element300.

The second insulating pattern 521 may be on a portion of the outersurface of the light emitting element 300, and may perform a function offixing (affixing) the light emitting element 300. During the process offabricating the display device 10, the light emitting element 300between the first electrode 210 and the second electrode 220 may befixed (affixed) by forming the second insulating layer 520 (or thesecond insulating pattern 521) thereon.

The third insulating pattern 522 may be between the light emittingelement 300 and the first insulating pattern 510P. The third insulatingpattern 522 may be formed such that, during the process of fabricatingthe display device 10, a space between the light emitting element 300and the first insulating pattern 510P is filled with a materialconstituting the second insulating layer 520. As described above, aspace may be formed between the light emitting element 300 and the firstinsulating pattern 510P, and the third insulating pattern 522 may beformed in the space. However, the present disclosure is not limitedthereto, and in some embodiments, the third insulating pattern 522 maybe omitted.

In an embodiment, a portion of a lower surface of the second insulatingpattern 521 may be in contact with the light emitting element 300 andanother portion thereof may be in contact with the first insulatingpattern 510P. The second insulating pattern 521 may include a firstlower surface in contact with the light emitting element 300 and asecond lower surface in contact with the first insulating pattern 510P.As shown in FIG. 5 , in a region in which the light emitting element 300is positioned, the second insulating pattern 521 may be on the lightemitting element 300 to form the first lower surface in contact with thelight emitting element 300. Further, as shown in FIG. 6 , in a region inwhich the light emitting element 300 is not positioned, the secondinsulating pattern 521 may be on the first insulating pattern 510P, andthe second lower surface in contact with the first insulating pattern510P may be formed. Further, the second insulating pattern 521 may alsobe in partial contact with an upper surface of the third insulatingpattern 522. The second insulating pattern 521 may extend in onedirection, e.g., the second direction DR2 between the first electrode210 and the second electrode 220, and may include a region overlappingthe light emitting element 300 and a region not overlapping the lightemitting element 300. In an embodiment, the first lower surface of thesecond insulating pattern 521 in the region overlapping the lightemitting element 300 may be in contact with the light emitting element300, and the second lower surface of the second insulating pattern 521in the region not overlapping the light emitting element 300 may be incontact with the first insulating pattern 510P and the third insulatingpattern 522.

The second insulating pattern 521 may be between the first contactelectrode 261 and the second contact electrode 262 and may insulate thefirst contact electrode 261 from the second contact electrode 262. Thesecond insulating pattern 521 may be in contact with the first contactelectrode 261 and the second contact electrode 262. The secondinsulating pattern 521 of the second insulating layer 520 may insulatethe first contact electrode 261 from the second contact electrode 262 soas to prevent (or reduce) electrical signals, which are transmitted fromthe electrodes 210 and 220, from being transmitted through the firstcontact electrode 261 and the second contact electrode 262.

According to one embodiment, a width W2 of the second insulating pattern521, measured in the first direction DR1, may be smaller than the lengthW1 of the light emitting element 300. Further, the width W2 of thesecond insulating pattern 521 may be smaller than the width W4 of thefirst insulating pattern 510P. The second insulating pattern 521 mayhave the width W2 that is smaller than the length W1 of the lightemitting element 300 so as to allow both end portions of the lightemitting element 300 to be exposed. The first contact electrode 261 andthe second contact electrode 262 may be respectively in contact with theboth end portions of the light emitting element 300 and may also be incontact with side surfaces of the light emitting element 300, which maybe exposed when the second insulating pattern 521 is not present. Thus,an area in which the first contact electrode 261 and the second contactelectrode 262 are in contact with the light emitting element 300 mayincrease, and a material constituting the contact electrode may beprevented (or reduced) from being disconnected.

The third insulating pattern 522 may be in the space between the firstinsulating pattern 510P and the light emitting element 300, and a widthW3, measured in the first direction DR1, of the third insulating pattern522 may be varied according to the step formed in the first insulatingpattern 510P. However, a width of a recessed portion formed in the firstinsulating pattern 510P, i.e., the width W3 of the third insulatingpattern 522, may be smaller than the length W1 of the light emittingelement 300 so as to allow the light emitting element 300 to be onto thefirst insulating pattern 510P. Further, in an embodiment, the width W2of the second insulating pattern 521 may be greater than the width W3 ofthe third insulating pattern 522. Because the second insulating pattern521 has a width that is greater than that of the third insulatingpattern 522, the third insulating pattern 522 below the light emittingelement 300 may sufficiently fill the recessed portion formed in thefirst insulating pattern 510P. However, the present disclosure is notlimited thereto, and the widths W2 and W3 of the second insulatingpattern 521 and the third insulating pattern 522 may be variouslymodified.

According to one embodiment, the second insulating pattern 521 mayinclude a first upper surface 521U which is not in contact with thefirst contact electrode 261 or the second contact electrode 262. In theprocess of fabricating the display device 10, the first contactelectrode 261 and the second contact electrode 262 may be formed by alift off process simultaneously (or concurrently) in one process. Here,a lift off layer PR (see FIG. 13 ) may be on a second insulator layer520′ (see FIG. 12 ) forming the second insulating layer 520. A portionof the second insulator layer 520′, on which the lift off layer PR ispositioned and remains, may form the second insulating pattern 521, andthe first contact electrode 261 and the second contact electrode 262 maybe in a region in which the lift off layer PR is not present. Becausethe lift off layer PR is on the first upper surface 521U of the secondinsulating pattern 521, a material constituting the contact electrode260 is not formed in that region. Accordingly, the first upper surface521U of the second insulating pattern 521, which is then exposed byremoving the lift off layer PR, may not be in contact with the firstcontact electrode 261 or the second contact electrode 262.

Further, according to one embodiment, the second insulating pattern 521may include a first contact surface CS1 in contact with the firstcontact electrode 261 and a second contact surface CS2 in contact withthe second contact electrode 262. The first contact surface CS1 may beon a first side surface of the second insulating pattern 521, and thesecond contact surface CS2 may be on a second side surface of the secondinsulating pattern 521. In the second insulating pattern 521, the firstupper surface 521U may not be in contact with the contact electrode 260,and only the first side surface and the second side surface may be incontact with the contact electrode 260. The first upper surface 521U ofthe second insulating pattern 521 may be a surface substantiallyparallel to the via layer 200, and the first side surface and the secondside surface may be surfaces crossing (e.g., perpendicular to) the vialayer 200. Thus, according to one embodiment, the first contact surfaceCS1, which is a surface on which the first contact electrode 261 is incontact with the second insulating pattern 521, and the second contactsurface CS2, which is a surface on which the second contact electrode262 is in contact with the second insulating pattern 521, may not beparallel to the first upper surface 521U of the second insulatingpattern 521. The first contact surface CS1 and the second contactsurface CS2 may be formed not parallel to the first upper surface 521Uof the second insulating pattern 521, may be formed crossing (e.g.,perpendicular to) the via layer 200.

Upper surfaces 261U and 262U in contact with the second insulatingpattern 521 may be defined in the first contact electrode 261 and thesecond contact electrode 262. The first contact electrode 261 mayinclude a second upper surface 261U, which is an upper surface of aportion of the first contact electrode 261 connected to the firstcontact surface CS1, and the second contact electrode 262 may include athird upper surface 262U, which is an upper surface of a portion of thesecond contact electrode 262 connected to the second contact surfaceCS2. According to one embodiment, the first upper surface 521U of thesecond insulating pattern 521 may be coplanar with the second uppersurface 261U of the first contact electrode 261 and the third uppersurface 262U of the second contact electrode 262. For example, the firstupper surface 521U of the second insulating pattern 521 may form thesame flat (or substantially flat) surface together with the second uppersurface 261U and the third upper surface 262U.

The first contact electrode 261 and the second contact electrode 262 maybe formed by the lift off process. A material constituting (for forming)the contact electrode may not be formed on the first upper surface 521Uof the second insulating pattern 521 and may be formed on only the sidesurfaces of the second insulating pattern 521. The first contactelectrode 261 and the second contact electrode 262, which are formedafter the lift off layer PR is removed, may be formed on only the sidesurfaces of the second insulating pattern 521, and the second uppersurface 261U and the third upper surface 262U may be coplanar with thefirst upper surface 521U of the second insulating pattern 521. However,the present disclosure is not limited thereto, and in some embodiments,the second upper surface 261U and the third upper surface 262U may forma step with the first upper surface 521U of the second insulatingpattern 521. A more detailed description thereof will be made below.

In the display device 10, the lift off process is performed so that thefirst contact electrode 261 and the second contact electrode 262 may beformed in the same process, and the number of fabricating processes maybe reduced. Further, the second insulating pattern 521, which is formedby arranging the lift off layer PR, may be in contact with the contactelectrodes 261 and 262 on the side surfaces of the second insulatingpattern 521. Because of the width W2 of the second insulating pattern521 (which is smaller than the length W1 of the light emitting element300), a contact area between the light emitting element 300 and thecontact electrodes 261 and 262 may increase and disconnection of thematerial forming the contact electrodes 261 and 262 may be prevented orreduced.

FIG. 7 is a schematic view of a light emitting element according to oneembodiment.

The light emitting element 300 may be an LED. For example, the lightemitting element 300 may be an inorganic LED having a size of amicrometer unit or a nanometer unit and made of an inorganic material.Inorganic LEDs may be arranged between two electrodes in which polarityis formed by forming an electric field in a specific (e.g., set)direction between the two electrodes facing each other. The lightemitting elements 300 may be arranged between two electrodes due to anelectric field formed on the two electrodes.

The light emitting element 300 according to one embodiment may have ashape extending in one direction. The light emitting element 300 mayhave a shape of a rod, a wire, a tube, and/or the like. In anembodiment, the light emitting element 300 may be a cylindrical shape ora rod shape. However, the shape of the light emitting element 300 is notlimited thereto, and the light emitting element 300 may have a shape ofa cube, a rectangular parallelepiped, a polygonal pillar (such as ahexagonal pillar and/or the like), or may have a shape which extends inone direction and has a partially inclined outer surface. Thus, thelight emitting element 300 may have various suitable shapes. A pluralityof semiconductors included in the light emitting element 300, which willbe described in more detail below, may have a structure in which thesemiconductors are sequentially arranged or stacked in the onedirection.

The light emitting element 300 may include a semiconductor layer dopedwith a conductive-type (e.g., p-type or n-type) impurity. Thesemiconductor layer may receive an electric signal applied from anexternal power source and may emit light in a specific (e.g., set)wavelength range.

The light emitting element 300 according to one embodiment may emitlight in a specific (e.g., set) wavelength range. In an embodiment, theactive layer 330 may emit blue light in a central wavelength range of450 nm to 495 nm. However, the central wavelength range of the bluelight is not limited to the above-described range, and it should beunderstood that the central wavelength range includes any wavelengthrange that can be recognized as a blue color in the art. Further, thelight emitted from the active layer 330 of the light emitting element300 is not limited thereto, and the light may be green light in acentral wavelength range of 495 nm to 570 nm or red light in a centralwavelength range of 620 nm to 750 nm. Hereinafter, an example in whichthe light emitting element 300 emits blue light will be described.

Referring to FIG. 7 , the light emitting element 300 may include thefirst semiconductor layer 310, the second semiconductor layer 320, theactive layer 330, the electrode layer 370, and the insulating layer 380.

For example, the first semiconductor layer 310 may be an n-typesemiconductor having a first conductive type. For example, when thelight emitting element 300 emits light in a blue wavelength range, thefirst semiconductor layer 310 may include a semiconductor materialhaving a chemical formula of Al_(x)Ga_(y)In_(1-x-y)N (0≤x≤1, 0≤y≤1, and0≤x+y≤1). For example, the semiconductor material may be one or moreselected among AlGaInN, GaN, AlGaN, InGaN, AlN, and InN, which are dopedwith an n-type impurity. The first semiconductor layer 310 may be dopedwith a first conductive type dopant. For example, the first conductivetype dopant may be Si, Ge, Sn, and/or the like. In an embodiment, thefirst semiconductor layer 310 may be n-GaN doped with n-type Si. Alength of the first semiconductor layer 310 may range from 1.5 μm to 5μm, but the present disclosure is not limited thereto.

The second semiconductor layer 320 may be on the active layer 330 whichwill be described in more detail below. For example, the secondsemiconductor layer 320 may be a p-type semiconductor having a secondconductive type. For example, when the light emitting element 300 emitslight in a blue or green wavelength range, the second semiconductorlayer 320 may include a semiconductor material having a chemical formulaof Al_(x)Ga_(y)In_(1-x-y)N (0≤x≤1, 0≤y≤1, and 0≤x+y≤1). For example, thesemiconductor material may be one or more selected among AlGaInN, GaN,AlGaN, InGaN, AlN, and InN, which are doped with an p-type impurity. Thesecond semiconductor layer 320 may be doped with a second conductivetype dopant. For example, the second conductive type dopant may be Mg,Zn, Ca, Se, Ba, and/or the like. In an embodiment, the secondsemiconductor layer 320 may be p-GaN doped with p-type Mg. A length ofthe second semiconductor layer 320 may range from 0.05 μm to 0.10 μm,but the present disclosure is not limited thereto.

Although the first semiconductor layer 310 and the second semiconductorlayer 320 have been illustrated as being formed of one layer, thepresent disclosure is not limited thereto. According to someembodiments, the first semiconductor layer 310 and the secondsemiconductor layer 320 may further include additional layers, e.g., aclad layer and/or a tensile strain barrier reducing (TSBR) layer,according to a material of the active layer 330. A more detaileddescription thereof will be made below with reference to other drawings.

The active layer 330 may be between the first semiconductor layer 310and the second semiconductor layer 320. The active layer 330 may includea material having a single or multiple quantum well structure. When theactive layer 330 includes a material having a multiple quantum wellstructure, the active layer 330 may have a structure in which a quantumlayer and a well layer are alternately stacked. The active layer 330 mayemit light due to a combination of electron-hole pairs in response toelectrical signals applied through the first semiconductor layer 310 andthe second semiconductor layer 320. For example, when the active layer330 emits light in a blue wavelength range, the active layer 330 mayinclude a material such as AlGaN, AlGaInN, and/or the like. For example,when the active layer 330 has a multi-quantum well structure in which aquantum layer and a well layer are alternately stacked, the quantumlayer may include a material such as AlGaN and/or AlGaInN, and the welllayer may include a material such as GaN and/or AlInN. In an embodiment,the active layer 330 includes AlGaInN as a quantum layer and AlInN as awell layer. As described above, the active layer 330 may emit blue lightin a central wavelength range of 450 nm to 495 nm.

However, the present disclosure is not limited thereto, and the activelayer 330 may have a structure in which a semiconductor material havinga large band gap energy and a semiconductor material having a small bandgap energy are alternately stacked, or may include different group IIIand/or group V semiconductor materials according to emitted light in awavelength range. The active layer 330 is not limited to emit light inthe blue wavelength range, and in some cases, the active layer 330 mayemit light in a red or green wavelength range. A length of the activelayer 330 may range from 0.05 μm to 0.10 μm, but the present disclosureis not limited thereto.

The light emitted from the active layer 330 may be emitted to not onlyan outer surface of the light emitting element 300 in the lengthdirection, but also the both side surfaces of the light emitting element300. Directivity of the light emitted from the active layer 330 is notlimited in one direction.

The electrode layer 370 may be an ohmic contact electrode. However, thepresent disclosure is not limited thereto, and the electrode layer 370may be a Schottky contact electrode. The light emitting element 300 mayinclude at least one electrode layer 370. Although the light emittingelement 300 has been illustrated as including a single electrode layer370 in FIG. 7 , the present disclosure is not limited thereto. In somecases, the light emitting element 300 may include more electrode layers370 or the electrode layer 370 may be omitted. The description of thelight emitting element 300 provided herein may be applied even when thenumber of electrode layers 370 is varied or another structure is furtherincluded.

In the display device 10 according to one embodiment, when the lightemitting element 300 is electrically connected to the electrode or thecontact electrode, the electrode layer 370 may reduce resistance betweenthe light emitting element 300 and the electrode, or between the lightemitting element 300 and the contact electrode. The electrode layer 370may include a conductive metal. For example, electrode layer 370 mayinclude at least one selected among Al, titanium (Ti), In, gold (Au),Ag, ITO, IZO, and ITZO. Further, the electrode layer 370 may include asemiconductor material doped with an n-type or p-type impurity. Theelectrode layer 370 may include the same material or differentmaterials, but the present disclosure is not limited thereto.

The insulating layer 380 may surround the outer surfaces of theplurality of semiconductor layers and the electrode layers describedabove. In an embodiment, the insulating layer 380 may surround at leastthe outer surface of the active layer 330 and may extend in onedirection in which the light emitting element 300 extends. Theinsulating layer 380 may serve to protect the members of the lightemitting element 300. For example, the insulating layer 380 may beformed to surround side surfaces of the members and to expose the bothend portions of the light emitting element 300 in the length directionthereof.

In the drawings, the insulating layer 380 has been illustrated as beingformed to extend in the length direction of the light emitting element300 to cover from the first semiconductor layer 310 to the side surfaceof the electrode layer 370, but the present disclosure in not limitedthereto. When the insulating layer 380 covers only the outer surfaces ofsome semiconductor layers, including the active layer 330, or coversonly a portion of the outer surface of the electrode layer 370, theouter surface of the electrode layer 370 may be partially exposed. Inaddition, an upper surface of the insulating layer 380 may be formed tobe rounded in cross section in a region adjacent to at least one endportion of the light emitting element 300.

A thickness of the insulating layer 380 may range from 10 nm to 1.0 μm,but the present disclosure is not limited thereto. In some embodiments,the thickness of the insulating layer 380 may be about 40 nm.

The insulating layer 380 may include an insulating material such asSiO_(x), SiN_(x), SiO_(x)N_(y), AlN, Al₂O₃, and/or the like.Accordingly, it may be possible to prevent (or reduce the risk of) anelectrical short circuit which may occur when the active layer 330 is indirect contact with an electrode through which an electrical signal istransmitted to the light emitting element 300. Further, because theinsulating layer 380 protects the outer surface of the light emittingelement 300 including the active layer 330, it may be possible toprevent (or reduce the risk of) degradation in light emissionefficiency.

Further, in some embodiments, the outer surface of the insulating layer380 may be surface-treated. In the fabrication of the display device 10,the light emitting elements 300 may be arranged by being injected ontothe electrodes in a state of being distributed in a predetermined (orset) ink. Here, in order to allow the light emitting element 300 tomaintain the distributed state without being agglomerated with anotherlight emitting element 300 adjacent thereto in the ink, the insulatinglayer 380 may be hydrophobically or hydrophilically treated.

The light emitting element 300 may have a length h ranging from 1 μm to10 μm, or from 2 μm to 6 μm, and for example from 3 μm to 5 μm. Further,a diameter of the light emitting element 300 may range from 300 nm to700 nm, and an aspect ratio of the light emitting element 300 may rangefrom 1.2 to 100. However, the present disclosure is not limited thereto,and the plurality of light emitting elements 300 included in the displaydevice 10 may have different diameters according to a compositiondifference between the active layers 330. In some embodiments, thediameter of the light emitting element 300 may be about 500 nm.

Hereinafter, a method of fabricating the display device 10 will bedescribed with reference to other drawings.

FIG. 8 is a flowchart illustrating a method of fabricating a displaydevice according to one embodiment.

Referring to FIG. 8 , a method of fabricating the display device 10according to one embodiment may include forming the first electrode 210and the second electrode 220 on the via layer 200, forming the lightemitting element 300 between the first electrode 210 and the secondelectrode 220, and forming an insulating layer on the light emittingelement 300 (S100); forming the lift off layer PR on the insulatinglayer and patterning the insulating layer to form an insulating patternon the light emitting element 300 (S200); and forming a metal layer MTLon the first electrode 210, the second electrode 220, and the lift offlayer PR, and removing the lift off layer PR to form the first contactelectrode 261 in contact with one side surface of the insulating patternand the second contact electrode 262 in contact with the other sidesurface of the insulating pattern (S300).

The process of fabricating the display device 10 may include a lift-offprocess of forming the first contact electrode 261 and the secondcontact electrode 262. The first contact electrode 261 and the secondcontact electrode 262 formed through the lift-off process may besimultaneously (or concurrently) formed in one process and may becoplanar with the upper surface of the second insulating pattern 521,with which the first contact electrode 261 and the second contactelectrode 262 are in contact.

Hereinafter, the process of fabricating the display device 10 will bedescribed in more detail with reference to other drawings.

FIGS. 9 to 18 are cross-sectional views illustrating the process offabricating a display device according to one embodiment.

Referring to FIG. 9 first, the first inner bank 410, the second innerbank 420, the first electrode 210, and the second electrode 220 areformed on the via layer 200, and a first insulator layer 510′ is formedto cover the first inner bank 410, the second inner bank 420, the firstelectrode 210, and the second electrode 220. Because the structures ofthe first inner bank 410, the second inner bank 420, the first electrode210, and the second electrode 220, which are formed on the via layer200, are the same as those described above with reference to FIG. 4 , adetailed description thereof will not be repeated here.

Unlike the first insulating layer 510, the first insulator layer 510′may cover entireties of the members on the via layer 200. The openingsOP1 and OP2 exposing some portion of the first electrode 210 and thesecond electrode 220, respectively, may be formed in the first insulatorlayer 510′ in an operation to form the first insulating layer 510.

Next, referring to FIG. 10 , the light emitting element 300 ispositioned between the first electrode 210 and the second electrode 220on the first insulator layer 510′. A method of arranging the lightemitting elements 300 includes injecting a solution containing the lightemitting elements 300 onto the electrodes 210 and 220 and applying anelectrical signal to each of the electrodes 210 and 220 to form anelectric field on the electrodes 210 and 220. The electric field maytransmit a dielectrophoretic force to the light emitting elements 300distributed in the solution, and the light emitting elements 300 may bearranged between the first electrode 210 and the second electrode 220 onthe first insulator layer 510′ due to the dielectrophoretic force. Thelight electrodes 210 and 220, and the light emitting elements havealready been described herein above, and therefore, a duplicativedescription thereof will not be repeated here.

Next, referring to FIG. 11 , a portion of the first insulator layer 510′is patterned to form the openings OP1 and OP2 partially exposing thefirst electrode 210 and the second electrode 220, respectively. Theopenings OP1 and OP2 may include a first opening OP1 exposing the firstelectrode 210 and a second opening OP2 exposing the second electrode220. The first opening OP1 and the second opening OP2 may expose regionsof the electrodes 210 and 220 located on the inner banks 410 and 420,respectively. The openings OP1 and OP2 are formed in the first insulatorlayer 510′ so that the first insulating layer 510 including the firstinsulating pattern 510P may be formed. A description of the firstinsulating layer 510 is the same as described above.

Next, referring to FIG. 12 , the second insulator layer 520′ is formedto cover the first insulating layer 510, the exposed first electrode 210and the second electrode 220, and the light emitting element 300. Thesecond insulator layer 520′ may be patterned in a subsequent process toform the second insulating layer 520. In an embodiment, the secondinsulator layer 520′ may include an organic insulating material. Thesecond insulator layer 520′ may be formed to surround at least the outersurface of the light emitting element 300 and may fill in a space 522′(in FIG. 12 ), which is formed between the light emitting element 300and the first insulating pattern 510P. The second insulator layer 520′filling the space 522′ may constitute the third insulating pattern 522of the second insulating layer 520.

Next, referring to FIGS. 13 and 14 , the lift off layer PR is formed onthe second insulator layer 520′, and the second insulator layer 520′ ispatterned along the lift off layer PR to form the second insulatinglayer 520. A type (or kind) of the lift off layer PR is not particularlylimited as long as it can serve as a mask in the patterning process. Thelift off layer PR may be a photoresist. A process of patterning thesecond insulator layer 520′ may be a suitable etching process. Forexample, the second insulator layer 520′ may be patterned through a dryetching process. However, the present disclosure is not limited thereto.

The lift off layer PR may be in a region overlapping the light emittingelement 300 on the second insulator layer 520′. A region of the secondinsulator layer 520′, in which the lift off layer PR is positioned, mayremain without being removed in a subsequent process so that the secondinsulating pattern 521 may be formed. In some embodiments, a width W5,measured in the first direction DR1, of the lift off layer PR may besmaller than a length of the light emitting element 300, and may besubstantially the same as the width of the second insulating pattern521. As shown in FIG. 14 , when the second insulator layer 520′ ispatterned along the lift off layer PR, a region in which the lift offlayer PR is placed may form the second insulating pattern 521, and thesecond insulator layer 520′ located below the light emitting element 300may form the third insulating pattern 522. In order to allow the secondinsulating pattern 521 to have a width that is smaller than the lengthof the light emitting element 300, the width W5 of the lift off layer PRmay be smaller than the length of the light emitting element 300.However, the present disclosure is not limited thereto.

When the second insulator layer 520′ is patterned along the lift offlayer PR, both end portions of the light emitting element 300 may beexposed. Here, the width of the second insulating pattern 521 may becontrolled and, additionally, the extent to which side surfaces of bothend portions of the light emitting element 300 are exposed may becontrolled by adjusting the width W5 of the lift off layer PR. When thewidth W5 of the lift off layer PR is greater than the length of thelight emitting element 300, both end portions of the light emittingelement 300 may not be sufficiently exposed. In this case, both endportions of the light emitting element 300 may not be in smooth contactwith the contact electrodes 261 and 262, which are formed in asubsequent process. In order to prevent (or reduce) this issue, thewidth W5 of the lift off layer PR may be adjusted to have a range belowa predetermined (or set) level. For example, the second insulator layer520′ may be patterned to expose the side surfaces of both end portionsof the light emitting element 300 such that a contact area between thelight emitting element 300 and the contact electrodes 261 and 262 mayincrease.

Next, referring to FIG. 15 , the metal layer MTL is formed on the firstelectrode 210, the second electrode 220, the lift off layer PR, and thefirst insulating layer 510. The process of forming the metal layer MTLmay be performed through one or more suitable processes such as asputtering process, an atomic layer deposition (ALD) process, and/or thelike. The metal layer MTL may form the contact electrodes 261 and 262 ina subsequent process. For example, the metal layer MTL may include thesame material as the contact electrodes 261 and 262.

The metal layer MTL may be formed on an entirety of the via layer 200.In addition to the first insulating pattern 510P, the metal layer MTLmay be in contact with the first insulating layer 510, the exposed firstelectrode 210, the exposed second electrode 220, and the light emittingelement 300. The metal layer MTL may include a first metal layer MTL1 onthe first electrode 210 and in contact with one end portion of the lightemitting element 300, a second metal layer MTL2 on the second electrode220 and in contact with the other end portion of the light emittingelement 300, and a third metal layer MTL3 on the lift off layer PR.

In a subsequent process, the third metal layer MTL3 may be removedtogether with the lift off layer PR, and the first metal layer MTL1 andthe second metal layer MTL2 may respectively form the first contactelectrode 261 and the second contact electrode 262. The first metallayer MTL1 may be in contact with, including one end portion of thelight emitting element 300, the first side surface of the secondinsulating pattern 521, and the second metal layer MTL2 may be incontact with, including the other end portion of the light emittingelement 300, the second side surface of the second insulating pattern521.

In one or more embodiments, the metal layer MTL may also be formed onboth side surfaces of the lift off layer PR. However, when the metallayer MTL is formed by a sputtering process, the metal layer MTL formedon the lift off layer PR may have a thin thickness and thus may beeasily removed in a subsequent process.

Next, referring to FIG. 16 , the lift off layer PR is removed. The thirdmetal layer MTL3 may be removed simultaneously with the lift off layerPR, and the first upper surface 521U of the second insulating pattern521 may be exposed. Because the lift off layer PR is on the first uppersurface 521U of the second insulating pattern 521, the metal layer MTLis not formed there. Accordingly, the contact electrodes 261 and 262 maynot be present on the first upper surface 521U exposed by removing thelift off layer PR. The first contact electrode 261 and the secondcontact electrode 262 may be respectively in contact with the first sidesurface and the second side surface of the second insulating pattern 521to form the first contact surface CS1 and the second contact surfaceCS2. A description thereof is the same as the above description. Then,the display device 10 may be fabricated by forming the passivation layer550 on the entirety of the via layer 200.

The method of fabricating the display device 10 according to oneembodiment may simultaneously (or concurrently) form the first contactelectrode 261 and the second contact electrode 262 in one process usinga lift-off process. Thus, the first upper surface 521U of the secondinsulating pattern 521, which is exposed by removing the lift off layerPR, may be coplanar with the second upper surface 261U of the firstcontact electrode 261 and the third upper surface 262U of the secondcontact electrode 262. Further, according to one embodiment, the methodof fabricating the display device 10 may reduce the number of processesrequired to form the contact electrodes 261 and 262 and may prevent (orreduce) a contact failure between the contact electrodes 261 and 262 andboth end portions of the light emitting element 300.

In some embodiments, in a region in which the light emitting element 300is not positioned between the first electrode 210 and the secondelectrode 220, the second insulating pattern 521 and the thirdinsulating pattern 522 of the second insulating layer 520 may be incontact with each other.

Referring to FIGS. 17 and 18 , in the second insulating layer 520, whichis formed by patterning the second insulator layer 520′, the secondinsulating pattern 521 may be directly on the first insulating pattern510P and may be in contact with the third insulating pattern 522, whichis formed in the recessed space of the first insulating pattern 510P.For example, the lower surface of the second insulating pattern 521 maybe in contact with the first insulating pattern 510P and the thirdinsulating pattern 522. A detailed description thereof is the same asdescribed above.

In some embodiments, the second upper surface 261U of the first contactelectrode 261 and the third upper surface 262U of the second contactelectrode 262 may not be coplanar with the first upper surface 521U ofthe second insulating pattern 521.

FIG. 19 is a cross-sectional view illustrating a portion of a displaydevice according to another embodiment.

Referring to FIG. 19 , in a display device 10_1 according to oneembodiment, at least one of a second upper surface 261U_1 of a firstcontact electrode 261_1 and a third upper surface 262U_1 of a secondcontact electrode 262_1 may be spaced apart from a reference surfacewhich is formed by a first upper surface 521U_1 of a second insulatingpattern 521_1. The present embodiment is different from the embodimentof FIG. 5 in that a portion in which the second insulating pattern521_1, the first contact electrode 261_1, and the second contactelectrode 262_1 are not coplanar with each other is not included in theembodiment of FIG. 5 . Hereinafter, a duplicative description will notbe repeated and, instead, the following description will focus ondifferences of the embodiments being described from the embodimentsalready described herein above.

In the display device 10_1 of FIG. 19 , the first upper surface 521U_1of the second insulating pattern 521_1 may be spaced apart from thesecond upper surface 261U_1 of the first contact electrode 261_1 and thethird upper surface 262U_1 of the second contact electrode 262_1. When areference surface formed by the first upper surface 521U_1 is defined,the second upper surface 261U_1 and the third upper surface 262U_1 maybe spaced apart from the reference surface. As shown in the drawing, aheight Ha of the second insulating pattern 521_1 (measured from thelight emitting element 300 to the first upper surface 521U_1) may begreater than each of a height Hb of the first contact electrode 261_1(measured from the light emitting element 300 to the second uppersurface 261U_1) and a height Hc of the second contact electrode 262_1(measured from the light emitting element 300 to the third upper surface262U_1). Consequently, the second insulating pattern 521_1 may includean exposed surface (portion) 521S_1, of which both side surfaces are notin contact with the contact electrodes 261_1 and 262_1. The first uppersurface 521U_1, the second upper surface 261U_1, and third upper surface262U_1 may be substantially parallel to each other, but a step may beformed therebetween. The first upper surface 521U_1 of the secondinsulating pattern 521_1 may be formed at a higher position than thefirst contact electrode 261_1 and the second contact electrode 262_1,relative to the light emitting element 300.

Such a structure of the display device 10_1 may be formed, during thefabricating process, by further arranging a hard mask layer HM between asecond insulator layer 520′_1 and a lift off layer PR.

FIGS. 20 to 23 are cross-sectional views illustrating a process offabricating the display device of FIG. 19 .

Referring to FIGS. 20 to 23 , in the method of fabricating the displaydevice 10_1, the hard mask layer HM may be further formed between asecond insulator layer 520′_1 and the lift off layer PR. The hard masklayer HM may include a material having an etch selectivity with respectto the second insulator layer 520′_1. When the hard mask layer HM andthe second insulator layer 520′_1 are etched along the lift off layerPR, the hard mask layer HM may remain with the same width as the liftoff layer PR, whereas the second insulator layer 520′_1 may remain witha width that is smaller than that of the lift off layer PR. For example,as shown in FIG. 21 , a width W2 of the second insulating pattern 521_1may be smaller than a width W6 of the hard mask layer HM, which remainsafter being etched. Then, in formation of a metal layer MTL_1, a portionof a side surface of the second insulating pattern 521_1 may be coveredby the hard mask layer HM, and a material constituting the metal layerMTL_1 may not be deposited on that portion.

As shown in FIG. 22 , a first metal layer MTL1_1 and a second metallayer MTL2_1 may be deposited on only a portion of the side surface ofthe second insulating pattern 521_1, and the first metal layer MTL1_1and the second metal layer MTL2_1 may not be formed in portions adjacentto the hard mask layer HM. A third metal layer MTL3_1 may be formed onthe hard mask layer HM and, as shown in FIG. 23 , the third metal layerMTL3_1 may be removed together with the hard mask layer HM. After thehard mask layer HM is removed, the first metal layer MTL1_1 and thesecond metal layer MTL2_1 may respectively form the first contactelectrode 261_1 and the second contact electrode 262_1, and regions ofboth side surfaces of the second insulating pattern 521_1 in which thematerials constituting the metal layer MTL_1 are not deposited may beexposed.

Since the process of fabricating the display device 10_1 of FIG. 19 mayinclude a process of forming the hard mask layer HM, some portions ofboth side surfaces of the second insulating pattern 521_1 may not be incontact with the first contact electrode 261_1 and the second contactelectrode 262_1.

FIG. 24 is a cross-sectional view illustrating a portion of a displaydevice according to yet another embodiment.

Referring to FIG. 24 , in a display device 10_2 according to oneembodiment, a third insulating pattern 522_2 of a second insulatinglayer 520 may be omitted. One side surface of a light emitting element300 on a first insulating pattern 510P_2 in a cross section may beentirely in contact with the first insulating pattern 510P_2. Theembodiment of FIG. 24 is different from the embodiment of FIG. 5 in thatthe third insulating pattern 522_2 is omitted. A description of otherconfigurations, except for the above description, is the same asdescribed above, and thus, a duplicative description of featuresdescribed herein above will not be repeated here.

The display device 10 may include more insulating layers, in addition tothose described herein. According to one embodiment, the display device10 may further include a third insulating layer 530 formed to protectthe first contact electrode 261.

FIG. 25 is a cross-sectional view illustrating a portion of a displaydevice according to yet another embodiment.

Referring to FIG. 25 , a display device 10_3 according to one embodimentmay further include a third insulating layer 530_3 on a first contactelectrode 261_3. The display device 10_3 according to the presentembodiment is different from the display device 10 of FIG. 4 in that thethird insulating layer 530_3 is further included so that a secondcontact electrode 262_3 is in contact with the third insulating layer530_3 (e.g., in contact with a side surface of the third insulatinglayer 530_3). Hereinafter, a duplicative description of the elementsalready described in connection with FIG. 4 will not be repeated here,and the following description will focus on a difference between theembodiment being described and that of FIG. 4 .

The display device 10_3 of FIG. 25 may be include the first contactelectrode 261_3 and the third insulating layer 530_3, which electricallyinsulates the first contact electrode 261_3 from the second contactelectrode 262_3. The third insulating layer 530_3 may cover the firstcontact electrode 261_3 and a second insulating pattern 521_3 of asecond insulating layer 520. The third insulating layer 530_3 may be incontact with the first contact electrode 261_3 and the second contactelectrode 262_3 on an upper surface of the second insulating pattern521_3. A lower surface of the third insulating layer 530_3 may be incontact with an upper surface of the first contact electrode 261_3 andthe upper surface of the second insulating pattern 521_3. One sidesurface of the third insulating layer 530_3 may be in contact with thesecond contact electrode 262_3.

In the display device 10_3, the first contact electrode 261_3 and thesecond contact electrode 262_3 may be formed using a lift-off process.In the display device 10_3 according to the present embodiment, thefirst contact electrode 261_3 and the second contact electrode 262_3 maybe formed through different lift-off processes. When the first contactelectrode 261_3 is formed together with the second insulating layer 520in the same lift-off process, the upper surface of the first contactelectrode 261_3 may be coplanar with the upper surface of the secondinsulating pattern 521_3 of the second insulating layer 520. The firstcontact electrode 261_3 may be in contact with one side surface of thesecond insulating pattern 521_3 and one end portion of a light emittingelement 300. When the second contact electrode 262_3 is formed togetherwith the third insulating layer 530_3 in the same lift-off process, anupper surface of the second contact electrode 262_3 may be coplanar withan upper surface of the third insulating layer 530_3. The second contactelectrode 262_3 may be in contact with the other side surface of thesecond insulating pattern 521_3, one side surface of the thirdinsulating layer 530_3, and the other end portion of the light emittingelement 300.

The third insulating layer 530_3 may be between the first contactelectrode 261_3 and the second contact electrode 262_3 to electricallyinsulate the first contact electrode 261_3 from the second contactelectrode 262_3. The one side surface of the third insulating layer530_3, which is in contact with the second contact electrode 262_3, maybe mutually arranged (e.g., aligned) with the other side surface of thesecond insulating pattern 521_3 (which is in contact with the secondcontact electrode 262_3). For example, the one side surface of the thirdinsulating layer 530_3 may be coplanar with the other side surface ofthe second insulating pattern 521_3. In some embodiments, the thirdinsulating layer 530 may include an inorganic insulating material, as ina first insulating layer 510.

A passivation layer 550 may be formed to protect the third insulatinglayer 530 and a second contact electrode 262. A duplicative descriptionthereof will not be repeated here.

According to some embodiments, in a first electrode 210 and a secondelectrode 220, electrode stem 210S and 220S extending in the firstdirection DR1 may be omitted.

FIG. 26 is a plan view of one sub-pixel of the display device accordingto another embodiment.

Referring to FIG. 26 , in a display device 10_4, a first electrode 210_4and a second electrode 220_4 may extend in one direction, e.g., thesecond direction DR2. In the first electrode 210_4 and the secondelectrode 220_4, electrode stem 210S and 220S extending in the firstdirection DR1 may be omitted. The display device 10_4 of FIG. 26 isdifferent from the display device 10 of FIG. 2 in that the electrodestem 210S and 220S are omitted and one additional second electrode 220_4is further included. Hereinafter, a duplicative description of theelements described in connection with FIG. 2 will not be repeated here,and the following description will focus on differences between theembodiment being described and that of FIG. 2 .

As shown in FIG. 26 , a plurality of first electrodes 210_4 and aplurality of second electrodes 220_4 may extend in the second directionDR2 in each sub-pixel PXn. An outer bank 430 may also extend in thesecond direction DR2. The second electrode 220_4 and the outer bank 430may extend to another sub-pixel PXn adjacent thereto in the seconddirection DR2. Thus, sub-pixels PXn which are adjacent in the seconddirection DR2 may receive the same electrical signal from the secondelectrode 220_4.

Unlike the display device 10 of FIG. 2 , in the display device 10_4 ofFIG. 26 , a second electrode contact hole CNTS may be formed in each ofthe second electrodes 220_4. The second electrode 220 may beelectrically connected to a power electrode 162 of a circuit elementlayer PAL through the second electrode contact hole CNTS which islocated in each sub-pixel PXn.

The first electrode 210_4 may be formed to extend in the seconddirection DR2 to a boundary of each sub-pixel PXn. The sub-pixels PXnwhich are adjacent in the second direction DR2 may include the firstelectrodes 210_4 spaced apart from each other, and the first electrodes210_4 may receive different electrical signals through first electrodecontact holes CNTD. A shape of the first electrode 210_4 may be formedby forming the first electrode 210_4 to extend in the second directionDR2 and then disconnecting (e.g., breaking up) the first electrodes210_4 at a boundary between adjacent sub-pixels PXn during the processof fabricating the display device 10.

The outer bank 430 may be at the boundary between adjacent sub-pixelsPXn in the first direction DR1 and may extend in the second directionDR2. In some embodiments, the outer bank 430 may be at the boundarybetween adjacent sub-pixels PXn in the second direction DR2 and mayextend in the first direction DR1. A description of the outer bank 430is the same as the above description given with reference to FIG. 3 .Further, a first contact electrode 261_4 and a second contact electrode262_4, which are included in the display device 10_4 of FIG. 26 , aresubstantially the same as those of the display device 10 of FIG. 3 .

In FIG. 26 , two first electrodes 210_4 and two second electrodes 220_4have been illustrated as being alternately positioned and spaced apartfrom each other. However, the present disclosure is not limited thereto,and some electrodes may be omitted from the display device 10_4 or alarger number of electrodes may be formed therein.

In the embodiment of FIG. 26 , a plurality of insulating patterns may bepositioned between the first electrode 210_4 and the second electrode220_4. Although only a second insulating pattern 521_4 has beenillustrated in the drawing, a first insulating pattern 510P and a thirdinsulating pattern 522 may also be formed to overlap the secondinsulating pattern 521_4. The second insulating pattern 521_4 may extendin the second direction DR2 to be between the first electrode 210_4 andthe second electrode 220_4 and, like the first electrode 210_4, may beformed to extend to a boundary of each sub-pixel PXn. For example, alength of the second insulating pattern 521_4 measured in the seconddirection DR2 may be the same as that of the first electrode 210_4measured in the second direction DR2. However, the present disclosure isnot limited thereto, and, like the second electrode 220_4, the secondinsulating pattern 521_4 may also extend to another sub-pixel PXnadjacent thereto in the second direction DR2 to form a linear pattern ona front surface of the display device 10_4.

The structure of a light emitting element 300 is not limited to thatshown in FIG. 7 , and the light emitting element 300 may have anotherstructure.

FIG. 27 is a schematic view of a light emitting element according toanother embodiment. FIG. 28 is a cross-sectional view illustrating aportion of a display device including the light emitting element of FIG.27 .

Referring to FIG. 27 first, a light emitting element 300′ may have ashape extending in one direction and having a partially inclined sidesurface. For example, the light emitting element 300′ according to oneembodiment may have a partially conical shape.

The light emitting element 300′ may be formed such that a plurality oflayers are not stacked in one direction, and each of the plurality oflayers surrounds an outer surface of another layer. The light emittingelement 300′ of FIG. 27 may be formed such that a plurality ofsemiconductor layers surround at least a portion of an outer surface ofanother layer. The light emitting element 300′ may include asemiconductor core, of which at least portion partially extends in onedirection, and an insulating layer 380′ formed to surround thesemiconductor core. The semiconductor core may include a firstsemiconductor layer 310′, an active layer 330′, a second semiconductorlayer 320′, and an electrode layer 370′. The light emitting element 300′of FIG. 27 is the same as the light emitting element 300 of FIG. 7except that shapes of the constituting layers are partially different.Hereinafter, duplicative content will not be repeated and thedescription will focus on differences between the embodiments beingdescribed and those described herein above.

According to one embodiment, the first semiconductor layer 310′ mayextend in one direction and both end portions thereof may be formed tobe inclined (e.g., narrowed) toward a central portion thereof. The firstsemiconductor layer 310′ of FIG. 27 may have a rod-shaped or cylindricalmain body and end portions having inclined side surfaces on upper andlower portions of the main body. An upper end portion of the main bodymay have a slope that is steeper than that of a lower end portionthereof.

The active layer 330′ may surround an outer surface of the main body ofthe first semiconductor layer 310′. The active layer 330′ may have anannular shape extending in one direction. The active layer 330′ may notbe formed on upper and lower end portions of the first semiconductorlayer 310′. The active layer 330′ may be formed on only a non-inclinedside surface of the first semiconductor layer 310′. However, the presentdisclosure is not limited thereto. Accordingly, light emitted from theactive layer 330′ may be emitted to not only both end portions of thelight emitting element 300′ in a length direction but also both sidesurfaces thereof based on (along) the length direction. When comparedwith the light emitting element 300 of FIG. 7 , the light emittingelement 300′ of FIG. 27 may include the active layer 330′ having alarger area, thereby emitting a larger amount of light.

The second semiconductor layer 320′ may surround an outer surface of theactive layer 330′ and the upper end portion of the first semiconductorlayer 310′. The second semiconductor layer 320′ may include an annularmain body extending in one direction and an upper end portion having aninclined side surface. For example, the second semiconductor layer 320′may be in direct contact with a side surface of the active layer 330′parallel thereto and the inclined upper end portion of the firstsemiconductor layer 310′. However, the second semiconductor layer 320′is not formed in the lower end portion of the first semiconductor layer310′.

The electrode layer 370′ may surround an outer surface of the secondsemiconductor layer 320′. For example, a shape of the electrode layer370′ may be substantially the same as that of the second semiconductorlayer 320′. In some embodiments, the electrode layer 370′ may be in fullcontact with the outer surface of the second semiconductor layer 320′.

The insulating layer 380′ may surround outer surfaces of the electrodelayer 370′ and the first semiconductor layer 310′. The insulating layer380′ may be in direct contact with the electrode layer 370′, the lowerend portion of the first semiconductor layer 310′ and exposed lower endportions of the active layer 330′, and the second semiconductor layer320′.

FIG. 28 is a partial cross-sectional view of a display device 10including the light emitting element 300′ of FIG. 27 . FIG. 28 shows aportion of area Xb-Xb′ of FIG. 4 . Referring to FIG. 28 , the displaydevice 10 according to one embodiment may include the light emittingelement 300′ of FIG. 27 . The display device 10 of FIG. 28 is the sameas the display device 10 of FIG. 4 except that a structure of the lightemitting element 300′ is different. Hereinafter, a duplicate descriptionof the elements described in connection with FIG. 4 will not be repeatedhere, and the following description will focus on differences betweenthe embodiments being described and those of FIG. 4 .

As described above, the light emitting element 300′ may include aplurality of layers and may be between the first electrode 210 and thesecond electrode 220. The plurality of layers of the light emittingelement 300′ may be arranged in a direction parallel to the via layer200 (e.g., to the extension direction of the via layer 200). Accordingto one embodiment, the light emitting element 300′ may be positionedsuch that the via layer 200 is parallel to a direction in which the mainbody of the first semiconductor layer 310′ extends. In the lightemitting element 300′, the insulating layer 380′, the electrode layer370′, the second semiconductor layer 320′, the active layer 330′, andthe first semiconductor layer 310′ may be sequentially arranged on thefirst insulating layer 510 in a direction crossing (e.g., perpendicularto) the via layer 200. Further, because each layer of the light emittingelement 300′ is formed to surround an outer surface of another layer,the light emitting element 300′ on the display device 10 may have asymmetrical structure based on (relative to) the first semiconductorlayer 310′. For example, the light emitting element 300′ may have ashape in which the active layer 330′, the second semiconductor layer320′, the electrode layer 370′, and the insulating layer 380′ may besequentially stacked in a direction crossing (e.g., perpendicular to)the via layer 200 based on (relative to) the first semiconductor layer310′. However, the present disclosure is not limited thereto. The orderin which the plurality of layers of the light emitting element 300′ arearranged may be reversed. In some cases, when the light emitting element300′ has another structure, the plurality of layers may be arranged in adirection parallel to the via layer 200.

In the display device 10 of FIG. 28 , a portion of the insulating layer380′ of the light emitting element 300′ may be removed, and theelectrode layer 370′ and the first semiconductor layer 310′ may bepartially exposed. In the formation of the second insulating layer 520during the process of fabricating the display device 10, the insulatinglayer 380′ may be partially removed. The exposed region of the electrodelayer 370′ may be in contact with the first contact electrode 261, andthe exposed region of the first semiconductor layer 310′ may be incontact with the second contact electrode 262.

Further, the light emitting element 300′ may include a first end portionhaving an inclined side surface based on the main body and a second endportion having a diameter that is smaller than that of the main body. Inthe light emitting element 300′ positioned on the first insulating layer510, the side surface of the main body may be in partial contact withthe first insulating layer 510, e.g., the first insulating pattern 510P,and the first end portion and the second end portion of the lightemitting element 300′ may be spaced apart from the first insulatingpattern 510P. The second insulating layer 520 may be further positionedin a region in which the main body of the light emitting element 300′,the first end portion, and the second end portion are spaced apart fromthe first insulating pattern 510P. A description of other configurationsis the same as described above, and thus, a duplicative description offeatures described herein above will not be repeated here.

A method of fabricating a display device according to the embodimentscan include forming a plurality of contact electrodes by performing asingle lift off process. The method of fabricating a display device canreduce the number of processes of forming the contact electrode andsecure a contact area of the contact electrodes in contact with a lightemitting element by adjusting a width of a lift off layer.

Further, a display device according to the embodiments can include aplurality of insulating patterns, and the insulating patterns on thelight emitting element can include upper surfaces coplanar with thecontact electrodes. The contact electrodes are not formed on the uppersurfaces of the insulating patterns, and only side surfaces of theinsulating patterns can be in contact with the contact electrodes.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper,” “bottom,” “top” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or operation in addition tothe orientation depicted in the figures. For example, if the device inthe figures is turned over, elements described as “below” or “beneath”other elements or features would then be oriented “above” or “over” theother elements or features. Thus, the term “below” may encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations), and the spatiallyrelative descriptors used herein should be interpreted accordingly.

As used herein, the terms “substantially”, “about”, and similar termsare used as terms of approximation and not as terms of degree, and areintended to account for the inherent deviations in measured orcalculated values that would be recognized by those of ordinary skill inthe art.

Any numerical range recited herein is intended to include all sub-rangesof the same numerical precision subsumed within the recited range. Forexample, a range of “1.0 to 10.0” is intended to include all subrangesbetween (and including) the recited minimum value of 1.0 and the recitedmaximum value of 10.0, that is, having a minimum value equal to orgreater than 1.0 and a maximum value equal to or less than 10.0, suchas, for example, 2.4 to 7.6. Any maximum numerical limitation recitedherein is intended to include all lower numerical limitations subsumedtherein and any minimum numerical limitation recited in thisspecification is intended to include all higher numerical limitationssubsumed therein. Accordingly, Applicant reserves the right to amendthis specification, including the claims, to expressly recite anysub-range subsumed within the ranges expressly recited herein.

While the present disclosure has been described with reference to someexample embodiments thereof, those skilled in the art will appreciatethat many variations and modifications can be made to the preferredembodiments without substantially departing from the principles of thepresent disclosure. Therefore, the disclosed embodiments are used in ageneric and descriptive sense only and not for purposes of limitation.The spirit and scope of the present disclosure is set forth in thefollowing claims and their equivalents.

What is claimed is:
 1. A method of fabricating a display device, themethod comprising: forming a first electrode and a second electrode on asubstrate, forming a light emitting element on the first electrode andthe second electrode, forming an insulating layer on the light emittingelement; forming a lift off layer on the insulating layer and patterningthe insulating layer to form an insulating pattern on the light emittingelement; forming a metal layer on the first electrode, the secondelectrode, and the lift off layer, removing the lift off layer, andforming a first contact electrode in contact with one side surface ofthe insulating pattern and a second contact electrode in contact withanother side surface of the insulating pattern, wherein the insulatingpattern comprises a first upper surface not in contact with the firstcontact electrode or the second contact electrode.
 2. The method ofclaim 1, wherein the first contact electrode is in contact with thefirst electrode and one end portion of the light emitting element, andthe second contact electrode is in contact with the second electrode andanother end portion of the light emitting element.
 3. The method ofclaim 2, wherein an upper surface of the insulating pattern is not incontact with the first contact electrode or the second contactelectrode.
 4. The method of claim 3, wherein: the forming of the liftoff layer further comprises forming a hard mask layer between theinsulating layer and the lift off layer; and the insulating patterncomprises a region in which the one side surface and the other sidesurface are exposed and are not in contact with the first contactelectrode or the second contact electrode.